diff --git a/docs/auth/authenticate.md b/docs/auth/authenticate.md
index 740e5f3c1..d2fb11603 100644
--- a/docs/auth/authenticate.md
+++ b/docs/auth/authenticate.md
@@ -77,7 +77,7 @@ client := copilot.NewClient(nil)
 <summary><strong>.NET</strong></summary>
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 // Default: uses logged-in user credentials
 await using var client = new CopilotClient();
@@ -179,23 +179,23 @@ client := copilot.NewClient(&copilot.ClientOptions{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var userAccessToken = "token";
 await using var client = new CopilotClient(new CopilotClientOptions
 {
-    GithubToken = userAccessToken,
+    GitHubToken = userAccessToken,
     UseLoggedInUser = false,
 });
 ```
 <!-- /docs-validate: hidden -->
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 await using var client = new CopilotClient(new CopilotClientOptions
 {
-    GithubToken = userAccessToken,     // Token from OAuth flow
+    GitHubToken = userAccessToken,     // Token from OAuth flow
     UseLoggedInUser = false,           // Don't use stored CLI credentials
 });
 ```
diff --git a/docs/auth/byok.md b/docs/auth/byok.md
index 95b4a1c74..cb2f8cb90 100644
--- a/docs/auth/byok.md
+++ b/docs/auth/byok.md
@@ -142,7 +142,7 @@ func main() {
 <summary><strong>.NET</strong></summary>
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 await using var client = new CopilotClient();
 await using var session = await client.CreateSessionAsync(new SessionConfig
@@ -424,7 +424,7 @@ func main() {
 <summary><strong>.NET</strong></summary>
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var client = new CopilotClient(new CopilotClientOptions
 {
diff --git a/docs/features/custom-agents.md b/docs/features/custom-agents.md
index 71fd9b4b1..3d93f7589 100644
--- a/docs/features/custom-agents.md
+++ b/docs/features/custom-agents.md
@@ -173,7 +173,7 @@ session, _ := client.CreateSession(ctx, &copilot.SessionConfig{
 <summary><strong>.NET</strong></summary>
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 await using var client = new CopilotClient();
 await using var session = await client.CreateSessionAsync(new SessionConfig
@@ -585,13 +585,13 @@ _, err := session.SendAndWait(ctx, copilot.MessageOptions{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class SubAgentEventsExample
 {
     public static async Task Example(CopilotSession session)
     {
-        using var subscription = session.On(evt =>
+        using var subscription = session.On<SessionEvent>(evt =>
         {
             switch (evt)
             {
@@ -622,7 +622,7 @@ public static class SubAgentEventsExample
 <!-- /docs-validate: hidden -->
 
 ```csharp
-using var subscription = session.On(evt =>
+using var subscription = session.On<SessionEvent>(evt =>
 {
     switch (evt)
     {
diff --git a/docs/features/hooks.md b/docs/features/hooks.md
index db9ad72ec..c88c6e605 100644
--- a/docs/features/hooks.md
+++ b/docs/features/hooks.md
@@ -146,7 +146,7 @@ session, err := client.CreateSession(ctx, &copilot.SessionConfig{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class HooksExample
 {
@@ -348,7 +348,7 @@ session, _ := client.CreateSession(ctx, &copilot.SessionConfig{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class PermissionControlExample
 {
diff --git a/docs/features/image-input.md b/docs/features/image-input.md
index 286414c91..4aa564558 100644
--- a/docs/features/image-input.md
+++ b/docs/features/image-input.md
@@ -161,7 +161,7 @@ session.Send(ctx, copilot.MessageOptions{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class ImageInputExample
 {
@@ -193,7 +193,7 @@ public static class ImageInputExample
 <!-- /docs-validate: hidden -->
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 await using var client = new CopilotClient();
 await using var session = await client.CreateSessionAsync(new SessionConfig
@@ -376,7 +376,7 @@ session.Send(ctx, copilot.MessageOptions{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class BlobAttachmentExample
 {
diff --git a/docs/features/mcp.md b/docs/features/mcp.md
index f6c5a7d7e..6f715bd2e 100644
--- a/docs/features/mcp.md
+++ b/docs/features/mcp.md
@@ -136,7 +136,7 @@ func main() {
 ### .NET
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 await using var client = new CopilotClient();
 await using var session = await client.CreateSessionAsync(new SessionConfig
diff --git a/docs/features/session-persistence.md b/docs/features/session-persistence.md
index 374497711..5a1987227 100644
--- a/docs/features/session-persistence.md
+++ b/docs/features/session-persistence.md
@@ -109,7 +109,7 @@ session.SendAndWait(ctx, copilot.MessageOptions{Prompt: "Analyze my codebase"})
 ### C# (.NET)
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var client = new CopilotClient();
 
@@ -201,7 +201,7 @@ session.SendAndWait(ctx, copilot.MessageOptions{Prompt: "What did we discuss ear
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class ResumeSessionExample
 {
diff --git a/docs/features/skills.md b/docs/features/skills.md
index 6db0d60f3..516c11762 100644
--- a/docs/features/skills.md
+++ b/docs/features/skills.md
@@ -116,7 +116,7 @@ func main() {
 <summary><strong>.NET</strong></summary>
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 await using var client = new CopilotClient();
 await using var session = await client.CreateSessionAsync(new SessionConfig
@@ -244,7 +244,7 @@ session, _ := client.CreateSession(context.Background(), &copilot.SessionConfig{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class SkillsExample
 {
diff --git a/docs/features/steering-and-queueing.md b/docs/features/steering-and-queueing.md
index 7858a7d3f..ce4f4fba2 100644
--- a/docs/features/steering-and-queueing.md
+++ b/docs/features/steering-and-queueing.md
@@ -152,7 +152,7 @@ func main() {
 <summary><strong>.NET</strong></summary>
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 await using var client = new CopilotClient();
 await using var session = await client.CreateSessionAsync(new SessionConfig
@@ -361,7 +361,7 @@ session.Send(ctx, copilot.MessageOptions{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class QueueingExample
 {
diff --git a/docs/features/streaming-events.md b/docs/features/streaming-events.md
index a12440ee5..6bc560a48 100644
--- a/docs/features/streaming-events.md
+++ b/docs/features/streaming-events.md
@@ -161,13 +161,13 @@ session.On(func(event copilot.SessionEvent) {
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class StreamingEventsExample
 {
     public static async Task Example(CopilotSession session)
     {
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             if (evt is AssistantMessageDeltaEvent delta)
             {
@@ -180,7 +180,7 @@ public static class StreamingEventsExample
 <!-- /docs-validate: hidden -->
 
 ```csharp
-session.On(evt =>
+session.On<SessionEvent>(evt =>
 {
     if (evt is AssistantMessageDeltaEvent delta)
     {
diff --git a/docs/getting-started.md b/docs/getting-started.md
index 0836f2567..3a43fad7c 100644
--- a/docs/getting-started.md
+++ b/docs/getting-started.md
@@ -299,7 +299,7 @@ cargo run
 Create a new console project and add this to `Program.cs`:
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 await using var client = new CopilotClient();
 await using var session = await client.CreateSessionAsync(new SessionConfig
@@ -557,7 +557,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 Update `Program.cs`:
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 await using var client = new CopilotClient();
 await using var session = await client.CreateSessionAsync(new SessionConfig
@@ -568,7 +568,7 @@ await using var session = await client.CreateSessionAsync(new SessionConfig
 });
 
 // Listen for response chunks
-session.On(ev =>
+session.On<SessionEvent>(ev =>
 {
     if (ev is AssistantMessageDeltaEvent deltaEvent)
     {
@@ -800,17 +800,17 @@ tokio::spawn(async move {
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class EventSubscriptionExample
 {
     public static void Example(CopilotSession session)
     {
         // Subscribe to all events
-        var unsubscribe = session.On(ev => Console.WriteLine($"Event: {ev.Type}"));
+        var unsubscribe = session.On<SessionEvent>(ev => Console.WriteLine($"Event: {ev.Type}"));
 
         // Filter by event type using pattern matching
-        session.On(ev =>
+        session.On<SessionEvent>(ev =>
         {
             switch (ev)
             {
@@ -832,10 +832,10 @@ public static class EventSubscriptionExample
 
 ```csharp
 // Subscribe to all events
-var unsubscribe = session.On(ev => Console.WriteLine($"Event: {ev.Type}"));
+var unsubscribe = session.On<SessionEvent>(ev => Console.WriteLine($"Event: {ev.Type}"));
 
 // Filter by event type using pattern matching
-session.On(ev =>
+session.On<SessionEvent>(ev =>
 {
     switch (ev)
     {
@@ -1159,7 +1159,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 Update `Program.cs`:
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Extensions.AI;
 using System.ComponentModel;
 
@@ -1190,7 +1190,7 @@ await using var session = await client.CreateSessionAsync(new SessionConfig
     Tools = [getWeather],
 });
 
-session.On(ev =>
+session.On<SessionEvent>(ev =>
 {
     if (ev is AssistantMessageDeltaEvent deltaEvent)
     {
@@ -1647,7 +1647,7 @@ cargo run
 Create a new console project and update `Program.cs`:
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Extensions.AI;
 using System.ComponentModel;
 
@@ -1676,7 +1676,7 @@ await using var session = await client.CreateSessionAsync(new SessionConfig
 });
 
 // Listen for response chunks
-session.On(ev =>
+session.On<SessionEvent>(ev =>
 {
     if (ev is AssistantMessageDeltaEvent deltaEvent)
     {
@@ -2067,12 +2067,11 @@ let session = client
 <summary><strong>.NET</strong></summary>
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliUrl = "localhost:4321",
-    UseStdio = false
+    Connection = RuntimeConnection.ForUri("localhost:4321"),
 });
 
 // Use the client normally
diff --git a/docs/hooks/error-handling.md b/docs/hooks/error-handling.md
index 803032432..f36573f31 100644
--- a/docs/hooks/error-handling.md
+++ b/docs/hooks/error-handling.md
@@ -84,7 +84,7 @@ type ErrorOccurredHandler func(
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public delegate Task<ErrorOccurredHookOutput?> ErrorOccurredHandler(
     ErrorOccurredHookInput input,
@@ -226,7 +226,7 @@ session, _ := client.CreateSession(context.Background(), &copilot.SessionConfig{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class ErrorHandlingExample
 {
diff --git a/docs/hooks/hooks-overview.md b/docs/hooks/hooks-overview.md
index a5f5981f4..460813c26 100644
--- a/docs/hooks/hooks-overview.md
+++ b/docs/hooks/hooks-overview.md
@@ -124,7 +124,7 @@ func main() {
 <summary><strong>.NET</strong></summary>
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var client = new CopilotClient();
 
diff --git a/docs/hooks/post-tool-use.md b/docs/hooks/post-tool-use.md
index 47262415f..f3c6f6799 100644
--- a/docs/hooks/post-tool-use.md
+++ b/docs/hooks/post-tool-use.md
@@ -84,7 +84,7 @@ type PostToolUseHandler func(
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public delegate Task<PostToolUseHookOutput?> PostToolUseHandler(
     PostToolUseHookInput input,
@@ -219,7 +219,7 @@ session, _ := client.CreateSession(context.Background(), &copilot.SessionConfig{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class PostToolUseExample
 {
diff --git a/docs/hooks/pre-tool-use.md b/docs/hooks/pre-tool-use.md
index e3509dd0a..6e568d8a2 100644
--- a/docs/hooks/pre-tool-use.md
+++ b/docs/hooks/pre-tool-use.md
@@ -84,7 +84,7 @@ type PreToolUseHandler func(
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public delegate Task<PreToolUseHookOutput?> PreToolUseHandler(
     PreToolUseHookInput input,
@@ -228,7 +228,7 @@ session, _ := client.CreateSession(context.Background(), &copilot.SessionConfig{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class PreToolUseExample
 {
diff --git a/docs/hooks/session-lifecycle.md b/docs/hooks/session-lifecycle.md
index b4ff502d5..83b75a32f 100644
--- a/docs/hooks/session-lifecycle.md
+++ b/docs/hooks/session-lifecycle.md
@@ -88,7 +88,7 @@ type SessionStartHandler func(
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public delegate Task<SessionStartHookOutput?> SessionStartHandler(
     SessionStartHookInput input,
diff --git a/docs/hooks/user-prompt-submitted.md b/docs/hooks/user-prompt-submitted.md
index d5965f4a1..79e34249d 100644
--- a/docs/hooks/user-prompt-submitted.md
+++ b/docs/hooks/user-prompt-submitted.md
@@ -84,7 +84,7 @@ type UserPromptSubmittedHandler func(
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public delegate Task<UserPromptSubmittedHookOutput?> UserPromptSubmittedHandler(
     UserPromptSubmittedHookInput input,
@@ -209,7 +209,7 @@ session, _ := client.CreateSession(context.Background(), &copilot.SessionConfig{
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class UserPromptSubmittedExample
 {
diff --git a/docs/integrations/microsoft-agent-framework.md b/docs/integrations/microsoft-agent-framework.md
index 4da47104c..1802ddd4b 100644
--- a/docs/integrations/microsoft-agent-framework.md
+++ b/docs/integrations/microsoft-agent-framework.md
@@ -74,7 +74,7 @@ Wrap the Copilot SDK client as a MAF agent with a single method call. The result
 
 <!-- docs-validate: skip -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Agents.AI;
 
 await using var copilotClient = new CopilotClient();
@@ -146,7 +146,7 @@ Extend your Copilot agent with custom function tools. Tools defined through the
 
 <!-- docs-validate: skip -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Extensions.AI;
 using Microsoft.Agents.AI;
 
@@ -282,7 +282,7 @@ Run agents one after another, passing output from one to the next:
 
 <!-- docs-validate: skip -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Agents.AI;
 using Microsoft.Agents.AI.Orchestration;
 
@@ -395,7 +395,7 @@ Run multiple agents in parallel and aggregate their results:
 
 <!-- docs-validate: skip -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Agents.AI;
 using Microsoft.Agents.AI.Orchestration;
 
@@ -472,7 +472,7 @@ When building interactive applications, stream agent responses to show real-time
 
 <!-- docs-validate: skip -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Agents.AI;
 
 await using var copilotClient = new CopilotClient();
diff --git a/docs/setup/backend-services.md b/docs/setup/backend-services.md
index 655453667..d9dd508e5 100644
--- a/docs/setup/backend-services.md
+++ b/docs/setup/backend-services.md
@@ -215,15 +215,14 @@ response, _ := session.SendAndWait(ctx, copilot.MessageOptions{Prompt: message})
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var userId = "user1";
 var message = "Hello";
 
 var client = new CopilotClient(new CopilotClientOptions
 {
-    CliUrl = "localhost:4321",
-    UseStdio = false,
+    Connection = RuntimeConnection.ForUri("localhost:4321"),
 });
 
 await using var session = await client.CreateSessionAsync(new SessionConfig
@@ -240,8 +239,7 @@ var response = await session.SendAndWaitAsync(
 ```csharp
 var client = new CopilotClient(new CopilotClientOptions
 {
-    CliUrl = "localhost:4321",
-    UseStdio = false,
+    Connection = RuntimeConnection.ForUri("localhost:4321"),
 });
 
 await using var session = await client.CreateSessionAsync(new SessionConfig
diff --git a/docs/setup/github-oauth.md b/docs/setup/github-oauth.md
index 31a3b9001..6cba4a5b7 100644
--- a/docs/setup/github-oauth.md
+++ b/docs/setup/github-oauth.md
@@ -230,12 +230,12 @@ response, _ := session.SendAndWait(ctx, copilot.MessageOptions{Prompt: "Hello!"}
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 CopilotClient CreateClientForUser(string userToken) =>
     new CopilotClient(new CopilotClientOptions
     {
-        GithubToken = userToken,
+        GitHubToken = userToken,
         UseLoggedInUser = false,
     });
 
@@ -257,7 +257,7 @@ var response = await session.SendAndWaitAsync(
 CopilotClient CreateClientForUser(string userToken) =>
     new CopilotClient(new CopilotClientOptions
     {
-        GithubToken = userToken,
+        GitHubToken = userToken,
         UseLoggedInUser = false,
     });
 
diff --git a/docs/setup/local-cli.md b/docs/setup/local-cli.md
index 28bef7b20..e7da4d937 100644
--- a/docs/setup/local-cli.md
+++ b/docs/setup/local-cli.md
@@ -139,7 +139,7 @@ if response != nil {
 ```csharp
 var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = "/usr/local/bin/copilot",
+    Connection = RuntimeConnection.ForStdio(path: "/usr/local/bin/copilot"),
 });
 
 await using var session = await client.CreateSessionAsync(
diff --git a/docs/troubleshooting/debugging.md b/docs/troubleshooting/debugging.md
index 7092899fd..f01beafc7 100644
--- a/docs/troubleshooting/debugging.md
+++ b/docs/troubleshooting/debugging.md
@@ -73,7 +73,7 @@ client := copilot.NewClient(&copilot.ClientOptions{
 <!-- docs-validate: skip -->
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Extensions.Logging;
 
 // Using ILogger
@@ -164,7 +164,7 @@ func main() {
 ```csharp
 var client = new CopilotClient(new CopilotClientOptions
 {
-    CliArgs = new[] { "--log-dir", "/path/to/logs" }
+    Connection = RuntimeConnection.ForStdio(args: new[] { "--log-dir", "/path/to/logs" })
 });
 ```
 
diff --git a/docs/troubleshooting/mcp-debugging.md b/docs/troubleshooting/mcp-debugging.md
index eb98eb1bd..664826c6e 100644
--- a/docs/troubleshooting/mcp-debugging.md
+++ b/docs/troubleshooting/mcp-debugging.md
@@ -236,7 +236,7 @@ cd /expected/working/dir
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class McpDotnetConfigExample
 {
@@ -248,14 +248,14 @@ public static class McpDotnetConfigExample
             {
                 Command = @"C:\Tools\MyServer\MyServer.exe",
                 Args = new List<string>(),
-                Cwd = @"C:\Tools\MyServer",
+                WorkingDirectory = @"C:\Tools\MyServer",
                 Tools = new List<string> { "*" },
             },
             ["my-dotnet-tool"] = new McpStdioServerConfig
             {
                 Command = "dotnet",
                 Args = new List<string> { @"C:\Tools\MyTool\MyTool.dll" },
-                Cwd = @"C:\Tools\MyTool",
+                WorkingDirectory = @"C:\Tools\MyTool",
                 Tools = new List<string> { "*" },
             }
         };
@@ -269,7 +269,7 @@ public static class McpDotnetConfigExample
 {
     Command = @"C:\Tools\MyServer\MyServer.exe",  // Full path with .exe
     Args = new List<string>(),
-    Cwd = @"C:\Tools\MyServer",  // Set working directory
+    WorkingDirectory = @"C:\Tools\MyServer",  // Set working directory
     Tools = new List<string> { "*" },
 }
 
@@ -278,7 +278,7 @@ public static class McpDotnetConfigExample
 {
     Command = "dotnet",
     Args = new List<string> { @"C:\Tools\MyTool\MyTool.dll" },
-    Cwd = @"C:\Tools\MyTool",
+    WorkingDirectory = @"C:\Tools\MyTool",
     Tools = new List<string> { "*" },
 }
 ```
@@ -287,7 +287,7 @@ public static class McpDotnetConfigExample
 
 <!-- docs-validate: hidden -->
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 public static class McpNpxConfigExample
 {
diff --git a/dotnet/README.md b/dotnet/README.md
index 012c51c17..f01d87474 100644
--- a/dotnet/README.md
+++ b/dotnet/README.md
@@ -1,4 +1,4 @@
-# Copilot SDK
+# Copilot SDK
 
 SDK for programmatic control of GitHub Copilot CLI.
 
@@ -7,7 +7,7 @@ SDK for programmatic control of GitHub Copilot CLI.
 ## Installation
 
 ```bash
-dotnet add package GitHub.Copilot.SDK
+dotnet add package GitHub.Copilot
 ```
 
 ## Run the Samples
@@ -27,7 +27,7 @@ dotnet run --file dotnet/samples/ManualToolResume.cs
 ## Quick Start
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 // Create and start client
 await using var client = new CopilotClient();
@@ -43,7 +43,7 @@ await using var session = await client.CreateSessionAsync(new SessionConfig
 // Wait for the response using the session.idle event
 var done = new TaskCompletionSource();
 
-session.On(evt =>
+session.On<SessionEvent>(evt =>
 {
     if (evt is AssistantMessageEvent msg)
     {
@@ -72,20 +72,24 @@ new CopilotClient(CopilotClientOptions? options = null)
 
 **Options:**
 
-- `CliPath` - Path to CLI executable (default: `COPILOT_CLI_PATH` env var, or bundled CLI)
-- `CliArgs` - Extra arguments prepended before SDK-managed flags
-- `CliUrl` - URL of existing CLI server to connect to (e.g., `"localhost:8080"`). When provided, the client will not spawn a CLI process.
-- `Port` - Server port (default: 0 for random)
-- `UseStdio` - Use stdio transport instead of TCP (default: true)
-- `LogLevel` - Log level (default: "info")
-- `AutoStart` - Auto-start server (default: true)
-- `Cwd` - Working directory for the CLI process
-- `CopilotHome` - Base directory for Copilot data (session state, config, etc.). Sets `COPILOT_HOME` on the spawned CLI process. When not set, the CLI defaults to `~/.copilot`. Useful in restricted environments where only specific directories are writable. Ignored when using `CliUrl`.
-- `Environment` - Environment variables to pass to the CLI process
-- `Logger` - `ILogger` instance for SDK logging
+- `Connection` - How to connect to the Copilot runtime. Defaults to `null` (equivalent to `RuntimeConnection.ForStdio()` with the bundled runtime). See "RuntimeConnection" below.
+- `LogLevel` - Runtime log level. Accepts well-known values `CopilotLogLevel.None`, `Error`, `Warning`, `Info`, `Debug`, `All`. Defaults to null (the runtime's own default).
+- `WorkingDirectory` - Working directory for the runtime process.
+- `BaseDirectory` - Base directory for Copilot data (session state, config, etc.). Sets `COPILOT_HOME` on the spawned runtime process. When not set, the runtime defaults to `~/.copilot`. Useful in restricted environments where only specific directories are writable. Ignored when connecting via `RuntimeConnection.ForUri(...)`.
+- `EnableRemoteSessions` - Enables remote-session features.
+- `Environment` - Environment variables to pass to the runtime process.
+- `Logger` - `ILogger` instance for SDK logging.
 - `GitHubToken` - GitHub token for authentication. When provided, takes priority over other auth methods.
-- `UseLoggedInUser` - Whether to use logged-in user for authentication (default: true, but false when `GitHubToken` is provided). Cannot be used with `CliUrl`.
-- `Telemetry` - OpenTelemetry configuration for the CLI process. Providing this enables telemetry — no separate flag needed. See [Telemetry](#telemetry) below.
+- `UseLoggedInUser` - Whether to use logged-in user for authentication (default: true, but false when `GitHubToken` is provided). Cannot be used with `RuntimeConnection.ForUri(...)`.
+- `Telemetry` - OpenTelemetry configuration for the runtime process. Providing this enables telemetry — no separate flag needed. See [Telemetry](#telemetry) below.
+
+#### RuntimeConnection
+
+`CopilotClientOptions.Connection` describes how the SDK reaches a Copilot runtime. There are three flavors, all constructed via static factories:
+
+- `RuntimeConnection.ForStdio(path?, args?)` — spawns the runtime as a child process and communicates over stdio. This is the default when `Connection` is null.
+- `RuntimeConnection.ForTcp(port = 0, connectionToken?, path?, args?)` — spawns the runtime as a child process listening on a TCP port. `port = 0` auto-allocates; if a non-zero port is already in use, startup fails (no fallback). Use `CopilotClient.RuntimePort` after `StartAsync` to read the assigned port. `connectionToken` is required if other clients will connect via `RuntimeConnection.ForUri(...)`.
+- `RuntimeConnection.ForUri(url, connectionToken?)` — connects to an already-running runtime at `url` (e.g., `"localhost:8080"`). Does not spawn a process.
 
 #### Methods
 
@@ -153,23 +157,19 @@ Get the ID of the session currently displayed in the TUI. Only available when co
 
 Request the TUI to switch to displaying the specified session. Only available in TUI+server mode.
 
-##### `On(Action<SessionLifecycleEvent> handler): IDisposable`
+##### `OnLifecycle<T>(Action<T> handler): IDisposable where T : SessionLifecycleEvent`
 
-Subscribe to all session lifecycle events. Returns an `IDisposable` that unsubscribes when disposed.
+Subscribe to session lifecycle events. Pass a derived type to filter by kind, or `SessionLifecycleEvent` to receive every lifecycle event. Returns an `IDisposable` that unsubscribes when disposed.
 
 ```csharp
-using var subscription = client.On(evt =>
+// Receive every lifecycle event:
+using var subscription = client.OnLifecycle<SessionLifecycleEvent>(evt =>
 {
     Console.WriteLine($"Session {evt.SessionId}: {evt.Type}");
 });
-```
 
-##### `On(string eventType, Action<SessionLifecycleEvent> handler): IDisposable`
-
-Subscribe to a specific lifecycle event type. Use `SessionLifecycleEventTypes` constants.
-
-```csharp
-using var subscription = client.On(SessionLifecycleEventTypes.Foreground, evt =>
+// Only receive foreground events:
+using var foreground = client.OnLifecycle<SessionForegroundEvent>(evt =>
 {
     Console.WriteLine($"Session {evt.SessionId} is now in foreground");
 });
@@ -177,11 +177,11 @@ using var subscription = client.On(SessionLifecycleEventTypes.Foreground, evt =>
 
 **Lifecycle Event Types:**
 
-- `SessionLifecycleEventTypes.Created` - A new session was created
-- `SessionLifecycleEventTypes.Deleted` - A session was deleted
-- `SessionLifecycleEventTypes.Updated` - A session was updated
-- `SessionLifecycleEventTypes.Foreground` - A session became the foreground session in TUI
-- `SessionLifecycleEventTypes.Background` - A session is no longer the foreground session
+- `SessionCreatedEvent` — A new session was created
+- `SessionDeletedEvent` — A session was deleted
+- `SessionUpdatedEvent` — A session was updated
+- `SessionForegroundEvent` — A session became the foreground session in TUI
+- `SessionBackgroundEvent` — A session is no longer the foreground session
 
 ---
 
@@ -208,12 +208,12 @@ Send a message to the session.
 
 Returns the message ID.
 
-##### `On(SessionEventHandler handler): IDisposable`
+##### `On(Action<SessionEvent> handler): IDisposable`
 
 Subscribe to session events. Returns a disposable to unsubscribe.
 
 ```csharp
-var subscription = session.On(evt =>
+var subscription = session.On<SessionEvent>(evt =>
 {
     Console.WriteLine($"Event: {evt.Type}");
 });
@@ -226,7 +226,7 @@ subscription.Dispose();
 
 Abort the currently processing message in this session.
 
-##### `GetMessagesAsync(): Task<IReadOnlyList<SessionEvent>>`
+##### `GetEventsAsync(): Task<IReadOnlyList<SessionEvent>>`
 
 Get all events/messages from this session.
 
@@ -262,7 +262,7 @@ Sessions emit various events during processing. Each event type is a class that
 Use pattern matching to handle specific event types:
 
 ```csharp
-session.On(evt =>
+session.On<SessionEvent>(evt =>
 {
     switch (evt)
     {
@@ -330,7 +330,7 @@ var session = await client.CreateSessionAsync(new SessionConfig
 // Use TaskCompletionSource to wait for completion
 var done = new TaskCompletionSource();
 
-session.On(evt =>
+session.On<SessionEvent>(evt =>
 {
     switch (evt)
     {
@@ -558,7 +558,7 @@ if (session.Capabilities.Ui?.Elicitation == true)
         ["production", "staging", "dev"]);
 
     // Text input — returns string or null
-    string? name = await session.Ui.InputAsync("Project name:", new InputOptions
+    string? name = await session.Ui.InputAsync("Project name:", new UiInputOptions
     {
         Title = "Name",
         MinLength = 1,
@@ -566,7 +566,7 @@ if (session.Capabilities.Ui?.Elicitation == true)
     });
 
     // Generic elicitation with full schema control
-    ElicitationResult result = await session.Ui.ElicitationAsync(new ElicitationParams
+    ElicitationResult result = await session.Ui.ElicitAsync(new ElicitationParams
     {
         Message = "Configure deployment",
         RequestedSchema = new ElicitationSchema
@@ -738,7 +738,7 @@ An `OnPermissionRequest` handler is optional when you create or resume a session
 Use the built-in `PermissionHandler.ApproveAll` helper to allow every tool call without any checks:
 
 ```csharp
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var session = await client.CreateSessionAsync(new SessionConfig
 {
@@ -749,7 +749,7 @@ var session = await client.CreateSessionAsync(new SessionConfig
 
 ### Custom Permission Handler
 
-Provide your own `PermissionRequestHandler` delegate to inspect each request and apply custom logic:
+Provide your own permission handler (`Func<PermissionRequest, PermissionInvocation, Task<PermissionRequestResult>>`) to inspect each request and apply custom logic:
 
 ```csharp
 var session = await client.CreateSessionAsync(new SessionConfig
@@ -987,7 +987,7 @@ catch (Exception ex)
 ## Requirements
 
 - .NET 8.0 or later
-- GitHub Copilot CLI installed and in PATH (or provide custom `CliPath`)
+- GitHub Copilot CLI installed and in PATH (or provide custom `Connection = RuntimeConnection.ForStdio(path: ...)`)
 
 ## License
 
diff --git a/dotnet/samples/Chat.cs b/dotnet/samples/Chat.cs
index 6345dd05c..f748a4005 100644
--- a/dotnet/samples/Chat.cs
+++ b/dotnet/samples/Chat.cs
@@ -1,6 +1,6 @@
 #:project ../src/GitHub.Copilot.SDK.csproj
 
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 await using var client = new CopilotClient();
 await using var session = await client.CreateSessionAsync(new SessionConfig
@@ -8,7 +8,7 @@
     OnPermissionRequest = PermissionHandler.ApproveAll
 });
 
-using var _ = session.On(evt =>
+using var _ = session.On<SessionEvent>(evt =>
 {
     Console.ForegroundColor = ConsoleColor.Blue;
     switch (evt)
diff --git a/dotnet/samples/ManualToolResume.cs b/dotnet/samples/ManualToolResume.cs
index 7658dde11..becda7444 100644
--- a/dotnet/samples/ManualToolResume.cs
+++ b/dotnet/samples/ManualToolResume.cs
@@ -1,8 +1,8 @@
 #:project ../src/GitHub.Copilot.SDK.csproj
 
 using System.ComponentModel;
-using GitHub.Copilot.SDK;
-using GitHub.Copilot.SDK.Rpc;
+using GitHub.Copilot;
+using GitHub.Copilot.Rpc;
 using Microsoft.Extensions.AI;
 
 var tool = ManualToolDeclaration();
@@ -80,7 +80,7 @@ static async Task<T> WaitForEventAsync<T>(CopilotSession session, Func<T, bool>?
 {
     var tcs = new TaskCompletionSource<T>(TaskCreationOptions.RunContinuationsAsynchronously);
     IDisposable? subscription = null;
-    subscription = session.On(evt =>
+    subscription = session.On<SessionEvent>(evt =>
     {
         if (evt is T typed && (predicate?.Invoke(typed) ?? true))
         {
diff --git a/dotnet/src/ActionDisposable.cs b/dotnet/src/ActionDisposable.cs
index 815904c12..86230651e 100644
--- a/dotnet/src/ActionDisposable.cs
+++ b/dotnet/src/ActionDisposable.cs
@@ -2,7 +2,7 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 /// <summary>
 /// A disposable that invokes an action when disposed.
diff --git a/dotnet/src/Client.cs b/dotnet/src/Client.cs
index f314a519b..11f8c90c9 100644
--- a/dotnet/src/Client.cs
+++ b/dotnet/src/Client.cs
@@ -1,8 +1,8 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
+using GitHub.Copilot.Rpc;
 using Microsoft.Extensions.AI;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
@@ -17,7 +17,7 @@
 using System.Text.Json.Serialization;
 using System.Text.RegularExpressions;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 /// <summary>
 /// Provides a client for interacting with the Copilot CLI server.
@@ -41,7 +41,7 @@ namespace GitHub.Copilot.SDK;
 /// await using var session = await client.CreateSessionAsync(new() { OnPermissionRequest = PermissionHandler.ApproveAll, Model = "gpt-4" });
 ///
 /// // Handle events
-/// using var subscription = session.On(evt =>
+/// using var subscription = session.On&lt;SessionEvent&gt;(evt =>
 /// {
 ///     if (evt is AssistantMessageEvent assistantMessage)
 ///         Console.WriteLine(assistantMessage.Data?.Content);
@@ -71,28 +71,28 @@ public sealed partial class CopilotClient : IDisposable, IAsyncDisposable
     internal readonly ConcurrentDictionary<string, CopilotSession> _sessions = new();
 
     private readonly CopilotClientOptions _options;
+    private readonly RuntimeConnection _connection;
     private readonly ILogger _logger;
     private Task<Connection>? _connectionTask;
-    private volatile bool _disconnected;
     private bool _disposed;
     private readonly int? _optionsPort;
     private readonly string? _optionsHost;
-    private readonly string? _effectiveConnectionToken;
     private int? _actualPort;
     private int? _negotiatedProtocolVersion;
     private List<ModelInfo>? _modelsCache;
     private readonly SemaphoreSlim _modelsCacheLock = new(1, 1);
     private readonly Func<CancellationToken, Task<IList<ModelInfo>>>? _onListModels;
-    private readonly List<Action<SessionLifecycleEvent>> _lifecycleHandlers = [];
-    private readonly Dictionary<string, List<Action<SessionLifecycleEvent>>> _typedLifecycleHandlers = [];
+    private readonly List<LifecycleSubscription> _lifecycleHandlers = [];
     private readonly object _lifecycleHandlersLock = new();
     private ServerRpc? _serverRpc;
 
+    private sealed record LifecycleSubscription(Type EventType, Action<SessionLifecycleEvent> Handler);
+
     /// <summary>
     /// Gets the typed RPC client for server-scoped methods (no session required).
     /// </summary>
     /// <remarks>
-    /// The client must be started before accessing this property. Use <see cref="StartAsync"/> or set <see cref="CopilotClientOptions.AutoStart"/> to true.
+    /// The client must be started before accessing this property. Call <see cref="StartAsync"/> before use.
     /// </remarks>
     /// <exception cref="ObjectDisposedException">Thrown if the client has been disposed.</exception>
     /// <exception cref="InvalidOperationException">Thrown if the client is not started.</exception>
@@ -101,91 +101,77 @@ public sealed partial class CopilotClient : IDisposable, IAsyncDisposable
         : _serverRpc ?? throw new InvalidOperationException("Client is not started. Call StartAsync first.");
 
     /// <summary>
-    /// Gets the actual TCP port the CLI server is listening on, if using TCP transport.
+    /// Gets the actual TCP port the runtime is listening on, if using TCP transport.
     /// </summary>
-    public int? ActualPort => _actualPort;
+    public int? RuntimePort => _actualPort;
 
     /// <summary>
     /// Creates a new instance of <see cref="CopilotClient"/>.
     /// </summary>
     /// <param name="options">Options for creating the client. If null, default options are used.</param>
-    /// <exception cref="ArgumentException">Thrown when mutually exclusive options are provided (e.g., CliUrl with UseStdio or CliPath).</exception>
     /// <example>
     /// <code>
-    /// // Default options - spawns CLI server using stdio
+    /// // Default options - spawns the bundled runtime using stdio
     /// var client = new CopilotClient();
     ///
-    /// // Connect to an existing server
-    /// var client = new CopilotClient(new CopilotClientOptions { CliUrl = "localhost:3000", UseStdio = false });
+    /// // Connect to an existing runtime
+    /// var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri("localhost:3000") });
     ///
-    /// // Custom CLI path with specific log level
+    /// // Custom runtime path with specific log level
     /// var client = new CopilotClient(new CopilotClientOptions
     /// {
-    ///     CliPath = "/usr/local/bin/copilot",
-    ///     LogLevel = "debug"
+    ///     Connection = RuntimeConnection.ForStdio(path: "/usr/local/bin/copilot"),
+    ///     LogLevel = CopilotLogLevel.Debug
     /// });
     /// </code>
     /// </example>
     public CopilotClient(CopilotClientOptions? options = null)
     {
         _options = options ?? new();
+        _connection = _options.Connection ?? RuntimeConnection.ForStdio();
 
-        // Validate mutually exclusive options
-        if (!string.IsNullOrEmpty(_options.CliUrl) && (_options.UseStdio == true || _options.CliPath != null))
+        switch (_connection)
         {
-            throw new ArgumentException("CliUrl is mutually exclusive with UseStdio and CliPath");
-        }
+            case StdioRuntimeConnection:
+                break;
 
-        // When CliUrl is provided, force TCP mode (we connect to an external server, not spawn one)
-        if (!string.IsNullOrEmpty(_options.CliUrl))
-        {
-            _options.UseStdio = false;
-        }
-        else
-        {
-            _options.UseStdio ??= true;
-        }
+            case TcpRuntimeConnection tcp:
+                if (tcp.ConnectionToken is { Length: 0 })
+                {
+                    throw new ArgumentException("ConnectionToken must be a non-empty string or null.", nameof(options));
+                }
+                // Auto-generate a connection token when the SDK spawns the runtime over TCP
+                // so the loopback listener is safe by default.
+                tcp.ConnectionToken ??= Guid.NewGuid().ToString();
+                break;
 
-        // Validate auth options with external server
-        if (!string.IsNullOrEmpty(_options.CliUrl) && (!string.IsNullOrEmpty(_options.GitHubToken) || _options.UseLoggedInUser != null))
-        {
-            throw new ArgumentException("GitHubToken and UseLoggedInUser cannot be used with CliUrl (external server manages its own auth)");
-        }
+            case UriRuntimeConnection uri:
+                if (string.IsNullOrEmpty(uri.Url))
+                {
+                    throw new ArgumentException("UriRuntimeConnection.Url must be a non-empty string.", nameof(options));
+                }
+                if (!string.IsNullOrEmpty(_options.GitHubToken) || _options.UseLoggedInUser != null)
+                {
+                    throw new ArgumentException("GitHubToken and UseLoggedInUser cannot be combined with RuntimeConnection.ForUri (the existing runtime manages its own auth).", nameof(options));
+                }
+                var parsed = ParseRuntimeUrl(uri.Url);
+                _optionsHost = parsed.Host;
+                _optionsPort = parsed.Port;
+                break;
 
-        if (_options.TcpConnectionToken is not null)
-        {
-            if (_options.TcpConnectionToken.Length == 0)
-            {
-                throw new ArgumentException("TcpConnectionToken must be a non-empty string");
-            }
-            if (_options.UseStdio == true)
-            {
-                throw new ArgumentException("TcpConnectionToken cannot be used with UseStdio = true");
-            }
+            default:
+                throw new ArgumentException($"Unsupported RuntimeConnection type: {_connection.GetType().Name}", nameof(options));
         }
 
-        var sdkSpawnsCli = _options.UseStdio == false && string.IsNullOrEmpty(_options.CliUrl);
-        _effectiveConnectionToken = _options.TcpConnectionToken
-            ?? (sdkSpawnsCli ? Guid.NewGuid().ToString() : null);
-
         _logger = _options.Logger ?? NullLogger.Instance;
         _onListModels = _options.OnListModels;
-
-        // Parse CliUrl if provided
-        if (!string.IsNullOrEmpty(_options.CliUrl))
-        {
-            var uri = ParseCliUrl(_options.CliUrl!);
-            _optionsHost = uri.Host;
-            _optionsPort = uri.Port;
-        }
     }
 
     /// <summary>
-    /// Parses a CLI URL into a URI with host and port.
+    /// Parses a runtime URL into a URI with host and port.
     /// </summary>
     /// <param name="url">The URL to parse. Supports formats: "port", "host:port", "http://host:port".</param>
-    /// <returns>A <see cref="Uri"/> containing the parsed host and port.</returns>
-    private static Uri ParseCliUrl(string url)
+    private static Uri ParseRuntimeUrl(string url)
     {
         // If it's just a port number, treat as localhost
         if (int.TryParse(url, out var port))
@@ -209,17 +195,12 @@ private static Uri ParseCliUrl(string url)
     /// <param name="cancellationToken">A <see cref="CancellationToken"/> that can be used to cancel the operation.</param>
     /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
     /// <remarks>
-    /// <para>
     /// If the server is not already running and the client is configured to spawn one (default), it will be started.
-    /// If connecting to an external server (via CliUrl), only establishes the connection.
-    /// </para>
-    /// <para>
-    /// This method is called automatically when creating a session if <see cref="CopilotClientOptions.AutoStart"/> is true (default).
-    /// </para>
+    /// If connecting to an external runtime (via RuntimeConnection.ForUri), only establishes the connection.
     /// </remarks>
     /// <example>
     /// <code>
-    /// var client = new CopilotClient(new CopilotClientOptions { AutoStart = false });
+    /// var client = new CopilotClient();
     /// await client.StartAsync();
     /// // Now ready to create sessions
     /// </code>
@@ -231,7 +212,6 @@ public Task StartAsync(CancellationToken cancellationToken = default)
         async Task<Connection> StartCoreAsync(CancellationToken ct)
         {
             _logger.LogDebug("Starting Copilot client");
-            _disconnected = false;
 
             var startTimestamp = Stopwatch.GetTimestamp();
             Connection? connection = null;
@@ -239,16 +219,16 @@ async Task<Connection> StartCoreAsync(CancellationToken ct)
 
             try
             {
-                if (_optionsHost is not null && _optionsPort is not null)
+                if (_connection is UriRuntimeConnection)
                 {
-                    // External server (TCP)
+                    // External runtime
                     _actualPort = _optionsPort;
                     connection = await ConnectToServerAsync(null, _optionsHost, _optionsPort, null, ct);
                 }
                 else
                 {
                     // Child process (stdio or TCP)
-                    var (startedProcess, portOrNull, stderrBuffer) = await StartCliServerAsync(_options, _effectiveConnectionToken, _logger, ct);
+                    var (startedProcess, portOrNull, stderrBuffer) = await StartCliServerAsync(ct);
                     cliProcess = startedProcess;
                     _actualPort = portOrNull;
                     connection = await ConnectToServerAsync(cliProcess, portOrNull is null ? null : "localhost", portOrNull, stderrBuffer, ct);
@@ -522,7 +502,7 @@ private static (SystemMessageConfig? wireConfig, Dictionary<string, Func<string,
     /// <returns>A task that resolves to provide the <see cref="CopilotSession"/>.</returns>
     /// <remarks>
     /// Sessions maintain conversation state, handle events, and manage tool execution.
-    /// If the client is not connected and <see cref="CopilotClientOptions.AutoStart"/> is enabled (default),
+    /// If the client is not connected,
     /// this will automatically start the connection.
     /// </remarks>
     /// <example>
@@ -570,8 +550,8 @@ public async Task<CopilotSession> CreateSessionAsync(SessionConfig config, Cance
         session.RegisterPermissionHandler(config.OnPermissionRequest);
         session.RegisterCommands(config.Commands);
         session.RegisterElicitationHandler(config.OnElicitationRequest);
-        session.RegisterExitPlanModeHandler(config.OnExitPlanMode);
-        session.RegisterAutoModeSwitchHandler(config.OnAutoModeSwitch);
+        session.RegisterExitPlanModeHandler(config.OnExitPlanModeRequest);
+        session.RegisterAutoModeSwitchHandler(config.OnAutoModeSwitchRequest);
         if (config.OnUserInputRequest != null)
         {
             session.RegisterUserInputHandler(config.OnUserInputRequest);
@@ -586,9 +566,9 @@ public async Task<CopilotSession> CreateSessionAsync(SessionConfig config, Cance
         }
         if (config.OnEvent != null)
         {
-            session.On(config.OnEvent);
+            session.On<SessionEvent>(config.OnEvent);
         }
-        ConfigureSessionFsHandlers(session, config.CreateSessionFsHandler);
+        ConfigureSessionFsHandlers(session, config.CreateSessionFsProvider);
         RegisterSession(session);
         session.StartProcessingEvents();
         LoggingHelpers.LogTiming(_logger, LogLevel.Debug, null,
@@ -616,8 +596,8 @@ public async Task<CopilotSession> CreateSessionAsync(SessionConfig config, Cance
                 config.EnableSessionTelemetry,
                 (bool?)true,
                 config.OnUserInputRequest != null ? true : null,
-                config.OnExitPlanMode != null ? true : null,
-                config.OnAutoModeSwitch != null ? true : null,
+                config.OnExitPlanModeRequest != null ? true : null,
+                config.OnAutoModeSwitchRequest != null ? true : null,
                 hasHooks ? true : null,
                 config.WorkingDirectory,
                 config.Streaming is true ? true : null,
@@ -728,8 +708,8 @@ public async Task<CopilotSession> ResumeSessionAsync(string sessionId, ResumeSes
         session.RegisterPermissionHandler(config.OnPermissionRequest);
         session.RegisterCommands(config.Commands);
         session.RegisterElicitationHandler(config.OnElicitationRequest);
-        session.RegisterExitPlanModeHandler(config.OnExitPlanMode);
-        session.RegisterAutoModeSwitchHandler(config.OnAutoModeSwitch);
+        session.RegisterExitPlanModeHandler(config.OnExitPlanModeRequest);
+        session.RegisterAutoModeSwitchHandler(config.OnAutoModeSwitchRequest);
         if (config.OnUserInputRequest != null)
         {
             session.RegisterUserInputHandler(config.OnUserInputRequest);
@@ -744,9 +724,9 @@ public async Task<CopilotSession> ResumeSessionAsync(string sessionId, ResumeSes
         }
         if (config.OnEvent != null)
         {
-            session.On(config.OnEvent);
+            session.On<SessionEvent>(config.OnEvent);
         }
-        ConfigureSessionFsHandlers(session, config.CreateSessionFsHandler);
+        ConfigureSessionFsHandlers(session, config.CreateSessionFsProvider);
         RegisterSession(session);
         session.StartProcessingEvents();
         LoggingHelpers.LogTiming(_logger, LogLevel.Debug, null,
@@ -774,13 +754,13 @@ public async Task<CopilotSession> ResumeSessionAsync(string sessionId, ResumeSes
                 config.EnableSessionTelemetry,
                 (bool?)true,
                 config.OnUserInputRequest != null ? true : null,
-                config.OnExitPlanMode != null ? true : null,
-                config.OnAutoModeSwitch != null ? true : null,
+                config.OnExitPlanModeRequest != null ? true : null,
+                config.OnAutoModeSwitchRequest != null ? true : null,
                 hasHooks ? true : null,
                 config.WorkingDirectory,
                 config.ConfigDir,
                 config.EnableConfigDiscovery,
-                config.DisableResume is true ? true : null,
+                config.SuppressResumeEvent is true ? true : null,
                 config.Streaming is true ? true : null,
                 config.IncludeSubAgentStreamingEvents,
                 config.McpServers,
@@ -832,32 +812,6 @@ public async Task<CopilotSession> ResumeSessionAsync(string sessionId, ResumeSes
         return session;
     }
 
-    /// <summary>
-    /// Gets the current connection state of the client.
-    /// </summary>
-    /// <value>
-    /// The current <see cref="ConnectionState"/>: Disconnected, Connecting, Connected, or Error.
-    /// </value>
-    /// <example>
-    /// <code>
-    /// if (client.State == ConnectionState.Connected)
-    /// {
-    ///     var session = await client.CreateSessionAsync(new() { OnPermissionRequest = PermissionHandler.ApproveAll });
-    /// }
-    /// </code>
-    /// </example>
-    public ConnectionState State
-    {
-        get
-        {
-            if (_connectionTask == null) return ConnectionState.Disconnected;
-            if (_connectionTask.IsFaulted) return ConnectionState.Error;
-            if (!_connectionTask.IsCompleted) return ConnectionState.Connecting;
-            if (_disconnected) return ConnectionState.Disconnected;
-            return ConnectionState.Connected;
-        }
-    }
-
     /// <summary>
     /// Validates the health of the connection by sending a ping request.
     /// </summary>
@@ -1130,103 +1084,59 @@ public async Task SetForegroundSessionIdAsync(string sessionId, CancellationToke
     }
 
     /// <summary>
-    /// Subscribes to all session lifecycle events.
-    /// </summary>
-    /// <remarks>
-    /// Lifecycle events are emitted when sessions are created, deleted, updated,
-    /// or change foreground/background state (in TUI+server mode).
-    /// </remarks>
-    /// <param name="handler">A callback function that receives lifecycle events.</param>
-    /// <returns>An IDisposable that, when disposed, unsubscribes the handler.</returns>
-    /// <example>
-    /// <code>
-    /// using var subscription = client.On(evt =>
-    /// {
-    ///     Console.WriteLine($"Session {evt.SessionId}: {evt.Type}");
-    /// });
-    /// </code>
-    /// </example>
-    public IDisposable On(Action<SessionLifecycleEvent> handler)
-    {
-        ArgumentNullException.ThrowIfNull(handler);
-
-        lock (_lifecycleHandlersLock)
-        {
-            _lifecycleHandlers.Add(handler);
-        }
-
-        return new ActionDisposable(() =>
-        {
-            lock (_lifecycleHandlersLock)
-            {
-                _lifecycleHandlers.Remove(handler);
-            }
-        });
-    }
-
-    /// <summary>
-    /// Subscribes to a specific session lifecycle event type.
+    /// Subscribes to session lifecycle events of a specific kind.
     /// </summary>
-    /// <param name="eventType">The event type to listen for (use SessionLifecycleEventTypes constants).</param>
-    /// <param name="handler">A callback function that receives events of the specified type.</param>
-    /// <returns>An IDisposable that, when disposed, unsubscribes the handler.</returns>
+    /// <typeparam name="T">
+    /// The lifecycle event type to listen for. Pass a derived type such as
+    /// <see cref="SessionCreatedEvent"/> to filter by kind, or
+    /// <see cref="SessionLifecycleEvent"/> to receive every lifecycle event.
+    /// </typeparam>
+    /// <param name="handler">A callback invoked when a matching lifecycle event arrives.</param>
+    /// <returns>An <see cref="IDisposable"/> that, when disposed, unsubscribes the handler.</returns>
     /// <example>
     /// <code>
-    /// using var subscription = client.On(SessionLifecycleEventTypes.Foreground, evt =>
+    /// using var sub = client.OnLifecycle&lt;SessionForegroundEvent&gt;(evt =&gt;
     /// {
     ///     Console.WriteLine($"Session {evt.SessionId} is now in foreground");
     /// });
     /// </code>
     /// </example>
-    public IDisposable On(string eventType, Action<SessionLifecycleEvent> handler)
+    public IDisposable OnLifecycle<T>(Action<T> handler) where T : SessionLifecycleEvent
     {
-        ArgumentNullException.ThrowIfNull(eventType);
         ArgumentNullException.ThrowIfNull(handler);
 
+        var subscription = new LifecycleSubscription(typeof(T), evt => handler((T)evt));
+
         lock (_lifecycleHandlersLock)
         {
-            if (!_typedLifecycleHandlers.TryGetValue(eventType, out var handlers))
-            {
-                handlers = [];
-                _typedLifecycleHandlers[eventType] = handlers;
-            }
-
-            handlers.Add(handler);
+            _lifecycleHandlers.Add(subscription);
         }
 
         return new ActionDisposable(() =>
         {
             lock (_lifecycleHandlersLock)
             {
-                if (_typedLifecycleHandlers.TryGetValue(eventType, out var handlers))
-                {
-                    handlers.Remove(handler);
-                }
+                _lifecycleHandlers.Remove(subscription);
             }
         });
     }
 
     private void DispatchLifecycleEvent(SessionLifecycleEvent evt)
     {
-        List<Action<SessionLifecycleEvent>> typedHandlers;
-        List<Action<SessionLifecycleEvent>> wildcardHandlers;
-
+        List<LifecycleSubscription> snapshot;
         lock (_lifecycleHandlersLock)
         {
-            typedHandlers = _typedLifecycleHandlers.TryGetValue(evt.Type, out var handlers)
-                ? [.. handlers]
-                : [];
-            wildcardHandlers = [.. _lifecycleHandlers];
-        }
-
-        foreach (var handler in typedHandlers)
-        {
-            try { handler(evt); } catch { /* Ignore handler errors */ }
+            snapshot = [.. _lifecycleHandlers];
         }
 
-        foreach (var handler in wildcardHandlers)
+        var eventType = evt.GetType();
+        foreach (var subscription in snapshot)
         {
-            try { handler(evt); } catch { /* Ignore handler errors */ }
+            if (!subscription.EventType.IsAssignableFrom(eventType))
+            {
+                continue;
+            }
+            try { subscription.Handler(evt); } catch { /* Ignore handler errors */ }
         }
     }
 
@@ -1309,11 +1219,6 @@ private static IOException CreateCliExitedException(string message, StringBuilde
 
     private Task<Connection> EnsureConnectedAsync(CancellationToken cancellationToken)
     {
-        if (_connectionTask is null && !_options.AutoStart)
-        {
-            throw new InvalidOperationException($"Client not connected. Call {nameof(StartAsync)}() first.");
-        }
-
         // If already started or starting, this will return the existing task
         return (Task<Connection>)StartAsync(cancellationToken);
     }
@@ -1343,11 +1248,11 @@ private void ConfigureSessionFsHandlers(CopilotSession session, Func<CopilotSess
         if (createSessionFsHandler is null)
         {
             throw new InvalidOperationException(
-                "CreateSessionFsHandler is required in the session config when CopilotClientOptions.SessionFs is configured.");
+                "CreateSessionFsProvider is required in the session config when CopilotClientOptions.SessionFs is configured.");
         }
 
         var provider = createSessionFsHandler(session)
-            ?? throw new InvalidOperationException("CreateSessionFsHandler returned null.");
+            ?? throw new InvalidOperationException("CreateSessionFsProvider returned null.");
 
         if (_options.SessionFs.Capabilities?.Sqlite == true && provider is not ISessionFsSqliteProvider)
         {
@@ -1366,8 +1271,14 @@ private async Task VerifyProtocolVersionAsync(Connection connection, Cancellatio
         int? serverVersion;
         try
         {
+            var token = _connection switch
+            {
+                TcpRuntimeConnection tcp => tcp.ConnectionToken,
+                UriRuntimeConnection uri => uri.ConnectionToken,
+                _ => null,
+            };
             var connectResponse = await InvokeRpcAsync<ConnectResult>(
-                connection.Rpc, "connect", [new ConnectRequest { Token = _effectiveConnectionToken }], connection.StderrBuffer, cancellationToken);
+                connection.Rpc, "connect", [new ConnectRequest { Token = token }], connection.StderrBuffer, cancellationToken);
             serverVersion = (int)connectResponse.ProtocolVersion;
         }
         catch (IOException ex) when (ex.InnerException is RemoteRpcException remoteEx && IsUnsupportedConnectMethod(remoteEx))
@@ -1410,32 +1321,42 @@ private static bool IsUnsupportedConnectMethod(RemoteRpcException ex)
             || string.Equals(ex.Message, "Unhandled method connect", StringComparison.Ordinal);
     }
 
-    private static async Task<(Process Process, int? DetectedLocalhostTcpPort, StringBuilder StderrBuffer)> StartCliServerAsync(CopilotClientOptions options, string? connectionToken, ILogger logger, CancellationToken cancellationToken)
+    private async Task<(Process Process, int? DetectedLocalhostTcpPort, StringBuilder StderrBuffer)> StartCliServerAsync(CancellationToken cancellationToken)
     {
-        // Use explicit path, COPILOT_CLI_PATH env var (from options.Environment or process env), or bundled CLI - no PATH fallback
+        var options = _options;
+        var logger = _logger;
+        var childProcessConnection = (ChildProcessRuntimeConnection)_connection;
+        var tcpConnection = _connection as TcpRuntimeConnection;
+        var useStdio = _connection is StdioRuntimeConnection;
+
+        // Use explicit path, COPILOT_CLI_PATH env var (from options.Environment or process env), or bundled runtime - no PATH fallback
         var envCliPath = options.Environment is not null && options.Environment.TryGetValue("COPILOT_CLI_PATH", out var envValue) ? envValue
             : System.Environment.GetEnvironmentVariable("COPILOT_CLI_PATH");
-        var cliPath = options.CliPath
+        var cliPath = childProcessConnection.Path
             ?? envCliPath
             ?? GetBundledCliPath(out var searchedPath)
-            ?? throw new InvalidOperationException($"Copilot CLI not found at '{searchedPath}'. Ensure the SDK NuGet package was restored correctly or provide an explicit CliPath.");
-        var cliPathSource = options.CliPath is not null ? "Options" : envCliPath is not null ? "Environment" : "Bundled";
+            ?? throw new InvalidOperationException($"Copilot runtime not found at '{searchedPath}'. Ensure the SDK NuGet package was restored correctly or provide an explicit RuntimeConnection.ForStdio(path: ...) / RuntimeConnection.ForTcp(path: ...).");
+        var cliPathSource = childProcessConnection.Path is not null ? "Options" : envCliPath is not null ? "Environment" : "Bundled";
         var args = new List<string>();
 
-        if (options.CliArgs != null)
+        if (childProcessConnection.Args != null)
         {
-            args.AddRange(options.CliArgs);
+            args.AddRange(childProcessConnection.Args);
         }
 
-        args.AddRange(["--headless", "--no-auto-update", "--log-level", options.LogLevel]);
+        args.AddRange(["--headless", "--no-auto-update"]);
+        if (options.LogLevel is { } logLevel && !string.IsNullOrEmpty(logLevel.Value))
+        {
+            args.AddRange(["--log-level", logLevel.Value]);
+        }
 
-        if (options.UseStdio == true)
+        if (useStdio)
         {
             args.Add("--stdio");
         }
-        else if (options.Port > 0)
+        else if (tcpConnection is { Port: > 0 } tcp)
         {
-            args.AddRange(["--port", options.Port.ToString(CultureInfo.InvariantCulture)]);
+            args.AddRange(["--port", tcp.Port.ToString(CultureInfo.InvariantCulture)]);
         }
 
         // Add auth-related flags
@@ -1456,24 +1377,24 @@ private static bool IsUnsupportedConnectMethod(RemoteRpcException ex)
             args.AddRange(["--session-idle-timeout", options.SessionIdleTimeoutSeconds.Value.ToString(CultureInfo.InvariantCulture)]);
         }
 
-        if (options.Remote)
+        if (options.EnableRemoteSessions)
         {
             args.Add("--remote");
         }
 
         var (fileName, processArgs) = ResolveCliCommand(cliPath, args);
-        var configuredPort = options.UseStdio == true ? (int?)null : options.Port;
-        LogStartingCopilotCli(logger, cliPath, fileName, cliPathSource, options.UseStdio == true, configuredPort);
+        var configuredPort = useStdio ? (int?)null : tcpConnection?.Port;
+        LogStartingCopilotCli(logger, cliPath, fileName, cliPathSource, useStdio, configuredPort);
 
         var startInfo = new ProcessStartInfo
         {
             FileName = fileName,
             Arguments = string.Join(" ", processArgs.Select(ProcessArgumentEscaper.Escape)),
             UseShellExecute = false,
-            RedirectStandardInput = options.UseStdio == true,
+            RedirectStandardInput = useStdio,
             RedirectStandardOutput = true,
             RedirectStandardError = true,
-            WorkingDirectory = options.Cwd,
+            WorkingDirectory = options.WorkingDirectory,
             CreateNoWindow = true
         };
 
@@ -1494,14 +1415,14 @@ private static bool IsUnsupportedConnectMethod(RemoteRpcException ex)
             startInfo.Environment["COPILOT_SDK_AUTH_TOKEN"] = options.GitHubToken;
         }
 
-        if (!string.IsNullOrEmpty(connectionToken))
+        if (tcpConnection?.ConnectionToken is { Length: > 0 } token)
         {
-            startInfo.Environment["COPILOT_CONNECTION_TOKEN"] = connectionToken;
+            startInfo.Environment["COPILOT_CONNECTION_TOKEN"] = token;
         }
 
-        if (!string.IsNullOrEmpty(options.CopilotHome))
+        if (!string.IsNullOrEmpty(options.BaseDirectory))
         {
-            startInfo.Environment["COPILOT_HOME"] = options.CopilotHome;
+            startInfo.Environment["COPILOT_HOME"] = options.BaseDirectory;
         }
 
         // Set telemetry environment variables if configured
@@ -1547,7 +1468,7 @@ private static bool IsUnsupportedConnectMethod(RemoteRpcException ex)
             }, cancellationToken);
 
             var detectedLocalhostTcpPort = (int?)null;
-            if (options.UseStdio != true)
+            if (!useStdio)
             {
                 // Wait for port announcement
                 var portWaitTimestamp = Stopwatch.GetTimestamp();
@@ -1560,7 +1481,7 @@ private static bool IsUnsupportedConnectMethod(RemoteRpcException ex)
                     if (line is null)
                     {
                         await stderrReader;
-                        throw CreateCliExitedException("CLI process exited unexpectedly", stderrBuffer);
+                        throw CreateCliExitedException("Runtime process exited unexpectedly", stderrBuffer);
                     }
 
                     if (logger.IsEnabled(LogLevel.Debug))
@@ -1640,11 +1561,11 @@ private async Task<Connection> ConnectToServerAsync(Process? cliProcess, string?
         Stream inputStream, outputStream;
         NetworkStream? networkStream = null;
 
-        if (_options.UseStdio == true)
+        if (_connection is StdioRuntimeConnection)
         {
             if (cliProcess == null)
             {
-                throw new InvalidOperationException("CLI process not started");
+                throw new InvalidOperationException("Runtime process not started");
             }
 
             inputStream = cliProcess.StandardOutput.BaseStream;
@@ -1708,9 +1629,6 @@ private async Task<Connection> ConnectToServerAsync(Process? cliProcess, string?
             "CopilotClient.ConnectToServerAsync transport setup complete. Elapsed={Elapsed}",
             setupTimestamp);
 
-        // Transition state to Disconnected if the JSON-RPC connection drops
-        _ = rpc.Completion.ContinueWith(_ => _disconnected = true, CancellationToken.None, TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);
-
         _serverRpc = new ServerRpc(rpc);
 
         return new Connection(rpc, cliProcess, networkStream, stderrBuffer);
@@ -1730,7 +1648,7 @@ private static JsonSerializerOptions CreateSerializerOptions()
         options.TypeInfoResolverChain.Add(TypesJsonContext.Default);
         options.TypeInfoResolverChain.Add(CopilotSession.SessionJsonContext.Default);
         options.TypeInfoResolverChain.Add(SessionEventsJsonContext.Default);
-        options.TypeInfoResolverChain.Add(SDK.Rpc.RpcJsonContext.Default);
+        options.TypeInfoResolverChain.Add(GitHub.Copilot.Rpc.RpcJsonContext.Default);
 
         options.MakeReadOnly();
 
@@ -1798,13 +1716,19 @@ public void OnSessionEvent(string sessionId, JsonElement? @event)
 
         public void OnSessionLifecycle(string type, string sessionId, JsonElement? metadata)
         {
-            var evt = new SessionLifecycleEvent
+            SessionLifecycleEvent evt = type switch
             {
-                Type = type,
-                SessionId = sessionId
+                "session.created" => new SessionCreatedEvent(),
+                "session.deleted" => new SessionDeletedEvent(),
+                "session.updated" => new SessionUpdatedEvent(),
+                "session.foreground" => new SessionForegroundEvent(),
+                "session.background" => new SessionBackgroundEvent(),
+                _ => new SessionLifecycleEvent()
             };
 
-            if (metadata != null)
+            evt.Type = type;
+            evt.SessionId = sessionId;
+            if (metadata is not null)
             {
                 evt.Metadata = JsonSerializer.Deserialize(
                     metadata.Value.GetRawText(),
@@ -2083,7 +2007,7 @@ internal record ResumeSessionRequest(
         string? WorkingDirectory,
         string? ConfigDir,
         bool? EnableConfigDiscovery,
-        bool? DisableResume,
+        bool? SuppressResumeEvent,
         bool? Streaming,
         bool? IncludeSubAgentStreamingEvents,
         IDictionary<string, McpServerConfig>? McpServers,
@@ -2214,7 +2138,7 @@ internal partial class ClientJsonContext : JsonSerializerContext;
 /// back through Microsoft.Extensions.AI without JSON serialization.
 /// </summary>
 /// <param name="toolResult">The tool result to wrap.</param>
-public class ToolResultAIContent(ToolResultObject toolResult) : AIContent
+public sealed class ToolResultAIContent(ToolResultObject toolResult) : AIContent
 {
     /// <summary>
     /// Gets the underlying <see cref="ToolResultObject"/>.
diff --git a/dotnet/src/CopilotTool.cs b/dotnet/src/CopilotTool.cs
index 6adcee093..feed5be76 100644
--- a/dotnet/src/CopilotTool.cs
+++ b/dotnet/src/CopilotTool.cs
@@ -4,7 +4,7 @@
 
 using Microsoft.Extensions.AI;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 /// <summary>
 /// Provides helpers for defining Copilot tools.
@@ -23,7 +23,7 @@ public static class CopilotTool
     /// <param name="method">The delegate to invoke when the tool is called.</param>
     /// <param name="factoryOptions">The Microsoft.Extensions.AI options used to create the function.</param>
     /// <param name="toolOptions">Copilot-specific tool options.</param>
-    /// <returns>An <see cref="AIFunction"/> that can be added to <see cref="SessionConfig.Tools"/> or <see cref="ResumeSessionConfig.Tools"/>.</returns>
+    /// <returns>An <see cref="AIFunction"/> that can be added to <see cref="SessionConfigBase.Tools"/>.</returns>
     /// <remarks>
     /// This is a helper on top of <see cref="AIFunctionFactory.Create(Delegate, AIFunctionFactoryOptions)"/> that applies additional configuration to support
     /// Copilot tools, such as binding a <see cref="ToolInvocation"/> parameter and adding Copilot-specific metadata properties based on the provided
diff --git a/dotnet/src/Generated/Rpc.cs b/dotnet/src/Generated/Rpc.cs
index 2bd4910a2..db7ce9d4c 100644
--- a/dotnet/src/Generated/Rpc.cs
+++ b/dotnet/src/Generated/Rpc.cs
@@ -16,7 +16,7 @@
 using System.Text.Json.Serialization;
 using System.Threading;
 
-namespace GitHub.Copilot.SDK.Rpc;
+namespace GitHub.Copilot.Rpc;
 
 /// <summary>Server liveness response, including the echoed message, current server timestamp, and protocol version.</summary>
 public sealed class PingResult
@@ -7204,13 +7204,13 @@ public sealed class Converter : JsonConverter<ModelPickerCategory>
         /// <inheritdoc />
         public override ModelPickerCategory Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ModelPickerCategory value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ModelPickerCategory));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ModelPickerCategory));
         }
     }
 }
@@ -7272,13 +7272,13 @@ public sealed class Converter : JsonConverter<ModelPickerPriceCategory>
         /// <inheritdoc />
         public override ModelPickerPriceCategory Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ModelPickerPriceCategory value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ModelPickerPriceCategory));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ModelPickerPriceCategory));
         }
     }
 }
@@ -7337,13 +7337,13 @@ public sealed class Converter : JsonConverter<ModelPolicyState>
         /// <inheritdoc />
         public override ModelPolicyState Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ModelPolicyState value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ModelPolicyState));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ModelPolicyState));
         }
     }
 }
@@ -7405,13 +7405,13 @@ public sealed class Converter : JsonConverter<DiscoveredMcpServerType>
         /// <inheritdoc />
         public override DiscoveredMcpServerType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, DiscoveredMcpServerType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(DiscoveredMcpServerType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(DiscoveredMcpServerType));
         }
     }
 }
@@ -7467,13 +7467,13 @@ public sealed class Converter : JsonConverter<SessionFsSetProviderConventions>
         /// <inheritdoc />
         public override SessionFsSetProviderConventions Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SessionFsSetProviderConventions value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionFsSetProviderConventions));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionFsSetProviderConventions));
         }
     }
 }
@@ -7530,13 +7530,13 @@ public sealed class Converter : JsonConverter<ConnectedRemoteSessionMetadataKind
         /// <inheritdoc />
         public override ConnectedRemoteSessionMetadataKind Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ConnectedRemoteSessionMetadataKind value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ConnectedRemoteSessionMetadataKind));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ConnectedRemoteSessionMetadataKind));
         }
     }
 }
@@ -7593,13 +7593,13 @@ public sealed class Converter : JsonConverter<SessionContextHostType>
         /// <inheritdoc />
         public override SessionContextHostType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SessionContextHostType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionContextHostType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionContextHostType));
         }
     }
 }
@@ -7662,13 +7662,13 @@ public sealed class Converter : JsonConverter<SendAgentMode>
         /// <inheritdoc />
         public override SendAgentMode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SendAgentMode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SendAgentMode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SendAgentMode));
         }
     }
 }
@@ -7728,13 +7728,13 @@ public sealed class Converter : JsonConverter<SendAttachmentGithubReferenceType>
         /// <inheritdoc />
         public override SendAttachmentGithubReferenceType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SendAttachmentGithubReferenceType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SendAttachmentGithubReferenceType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SendAttachmentGithubReferenceType));
         }
     }
 }
@@ -7791,13 +7791,13 @@ public sealed class Converter : JsonConverter<SendMode>
         /// <inheritdoc />
         public override SendMode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SendMode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SendMode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SendMode));
         }
     }
 }
@@ -7857,13 +7857,13 @@ public sealed class Converter : JsonConverter<SessionLogLevel>
         /// <inheritdoc />
         public override SessionLogLevel Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SessionLogLevel value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionLogLevel));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionLogLevel));
         }
     }
 }
@@ -7935,13 +7935,13 @@ public sealed class Converter : JsonConverter<AuthInfoType>
         /// <inheritdoc />
         public override AuthInfoType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, AuthInfoType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AuthInfoType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AuthInfoType));
         }
     }
 }
@@ -7998,13 +7998,13 @@ public sealed class Converter : JsonConverter<WorkspacesWorkspaceDetailsHostType
         /// <inheritdoc />
         public override WorkspacesWorkspaceDetailsHostType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, WorkspacesWorkspaceDetailsHostType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(WorkspacesWorkspaceDetailsHostType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(WorkspacesWorkspaceDetailsHostType));
         }
     }
 }
@@ -8067,13 +8067,13 @@ public sealed class Converter : JsonConverter<InstructionsSourcesLocation>
         /// <inheritdoc />
         public override InstructionsSourcesLocation Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, InstructionsSourcesLocation value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(InstructionsSourcesLocation));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(InstructionsSourcesLocation));
         }
     }
 }
@@ -8145,13 +8145,13 @@ public sealed class Converter : JsonConverter<InstructionsSourcesType>
         /// <inheritdoc />
         public override InstructionsSourcesType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, InstructionsSourcesType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(InstructionsSourcesType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(InstructionsSourcesType));
         }
     }
 }
@@ -8220,13 +8220,13 @@ public sealed class Converter : JsonConverter<AgentInfoSource>
         /// <inheritdoc />
         public override AgentInfoSource Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, AgentInfoSource value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AgentInfoSource));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AgentInfoSource));
         }
     }
 }
@@ -8283,13 +8283,13 @@ public sealed class Converter : JsonConverter<TaskExecutionMode>
         /// <inheritdoc />
         public override TaskExecutionMode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, TaskExecutionMode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(TaskExecutionMode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(TaskExecutionMode));
         }
     }
 }
@@ -8355,13 +8355,13 @@ public sealed class Converter : JsonConverter<TaskStatus>
         /// <inheritdoc />
         public override TaskStatus Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, TaskStatus value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(TaskStatus));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(TaskStatus));
         }
     }
 }
@@ -8418,13 +8418,13 @@ public sealed class Converter : JsonConverter<TaskShellInfoAttachmentMode>
         /// <inheritdoc />
         public override TaskShellInfoAttachmentMode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, TaskShellInfoAttachmentMode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(TaskShellInfoAttachmentMode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(TaskShellInfoAttachmentMode));
         }
     }
 }
@@ -8484,13 +8484,13 @@ public sealed class Converter : JsonConverter<McpSamplingExecutionAction>
         /// <inheritdoc />
         public override McpSamplingExecutionAction Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, McpSamplingExecutionAction value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(McpSamplingExecutionAction));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(McpSamplingExecutionAction));
         }
     }
 }
@@ -8547,13 +8547,13 @@ public sealed class Converter : JsonConverter<McpSetEnvValueModeDetails>
         /// <inheritdoc />
         public override McpSetEnvValueModeDetails Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, McpSetEnvValueModeDetails value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(McpSetEnvValueModeDetails));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(McpSetEnvValueModeDetails));
         }
     }
 }
@@ -8610,13 +8610,13 @@ public sealed class Converter : JsonConverter<OptionsUpdateEnvValueMode>
         /// <inheritdoc />
         public override OptionsUpdateEnvValueMode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, OptionsUpdateEnvValueMode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(OptionsUpdateEnvValueMode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(OptionsUpdateEnvValueMode));
         }
     }
 }
@@ -8673,13 +8673,13 @@ public sealed class Converter : JsonConverter<ExtensionSource>
         /// <inheritdoc />
         public override ExtensionSource Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ExtensionSource value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ExtensionSource));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ExtensionSource));
         }
     }
 }
@@ -8742,13 +8742,13 @@ public sealed class Converter : JsonConverter<ExtensionStatus>
         /// <inheritdoc />
         public override ExtensionStatus Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ExtensionStatus value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ExtensionStatus));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ExtensionStatus));
         }
     }
 }
@@ -8802,13 +8802,13 @@ public sealed class Converter : JsonConverter<SlashCommandInputCompletion>
         /// <inheritdoc />
         public override SlashCommandInputCompletion Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SlashCommandInputCompletion value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SlashCommandInputCompletion));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SlashCommandInputCompletion));
         }
     }
 }
@@ -8868,13 +8868,13 @@ public sealed class Converter : JsonConverter<SlashCommandKind>
         /// <inheritdoc />
         public override SlashCommandKind Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SlashCommandKind value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SlashCommandKind));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SlashCommandKind));
         }
     }
 }
@@ -8934,13 +8934,13 @@ public sealed class Converter : JsonConverter<UIElicitationResponseAction>
         /// <inheritdoc />
         public override UIElicitationResponseAction Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, UIElicitationResponseAction value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(UIElicitationResponseAction));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(UIElicitationResponseAction));
         }
     }
 }
@@ -9000,13 +9000,13 @@ public sealed class Converter : JsonConverter<UIAutoModeSwitchResponse>
         /// <inheritdoc />
         public override UIAutoModeSwitchResponse Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, UIAutoModeSwitchResponse value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(UIAutoModeSwitchResponse));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(UIAutoModeSwitchResponse));
         }
     }
 }
@@ -9069,13 +9069,13 @@ public sealed class Converter : JsonConverter<UIExitPlanModeAction>
         /// <inheritdoc />
         public override UIExitPlanModeAction Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, UIExitPlanModeAction value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(UIExitPlanModeAction));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(UIExitPlanModeAction));
         }
     }
 }
@@ -9132,13 +9132,13 @@ public sealed class Converter : JsonConverter<PermissionsConfigureAdditionalCont
         /// <inheritdoc />
         public override PermissionsConfigureAdditionalContentExclusionPolicyScope Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, PermissionsConfigureAdditionalContentExclusionPolicyScope value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionsConfigureAdditionalContentExclusionPolicyScope));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionsConfigureAdditionalContentExclusionPolicyScope));
         }
     }
 }
@@ -9201,13 +9201,13 @@ public sealed class Converter : JsonConverter<PermissionsSetApproveAllSource>
         /// <inheritdoc />
         public override PermissionsSetApproveAllSource Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, PermissionsSetApproveAllSource value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionsSetApproveAllSource));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionsSetApproveAllSource));
         }
     }
 }
@@ -9264,13 +9264,13 @@ public sealed class Converter : JsonConverter<PermissionsModifyRulesScope>
         /// <inheritdoc />
         public override PermissionsModifyRulesScope Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, PermissionsModifyRulesScope value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionsModifyRulesScope));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionsModifyRulesScope));
         }
     }
 }
@@ -9327,13 +9327,13 @@ public sealed class Converter : JsonConverter<PermissionLocationType>
         /// <inheritdoc />
         public override PermissionLocationType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, PermissionLocationType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionLocationType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionLocationType));
         }
     }
 }
@@ -9393,13 +9393,13 @@ public sealed class Converter : JsonConverter<MetadataSnapshotCurrentMode>
         /// <inheritdoc />
         public override MetadataSnapshotCurrentMode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, MetadataSnapshotCurrentMode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(MetadataSnapshotCurrentMode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(MetadataSnapshotCurrentMode));
         }
     }
 }
@@ -9456,13 +9456,13 @@ public sealed class Converter : JsonConverter<MetadataSnapshotRemoteMetadataTask
         /// <inheritdoc />
         public override MetadataSnapshotRemoteMetadataTaskType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, MetadataSnapshotRemoteMetadataTaskType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(MetadataSnapshotRemoteMetadataTaskType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(MetadataSnapshotRemoteMetadataTaskType));
         }
     }
 }
@@ -9519,13 +9519,13 @@ public sealed class Converter : JsonConverter<WorkspaceSummaryHostType>
         /// <inheritdoc />
         public override WorkspaceSummaryHostType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, WorkspaceSummaryHostType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(WorkspaceSummaryHostType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(WorkspaceSummaryHostType));
         }
     }
 }
@@ -9582,13 +9582,13 @@ public sealed class Converter : JsonConverter<SessionWorkingDirectoryContextHost
         /// <inheritdoc />
         public override SessionWorkingDirectoryContextHostType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SessionWorkingDirectoryContextHostType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionWorkingDirectoryContextHostType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionWorkingDirectoryContextHostType));
         }
     }
 }
@@ -9648,13 +9648,13 @@ public sealed class Converter : JsonConverter<ShellKillSignal>
         /// <inheritdoc />
         public override ShellKillSignal Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ShellKillSignal value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ShellKillSignal));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ShellKillSignal));
         }
     }
 }
@@ -9711,13 +9711,13 @@ public sealed class Converter : JsonConverter<QueuePendingItemsKind>
         /// <inheritdoc />
         public override QueuePendingItemsKind Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, QueuePendingItemsKind value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(QueuePendingItemsKind));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(QueuePendingItemsKind));
         }
     }
 }
@@ -9774,13 +9774,13 @@ public sealed class Converter : JsonConverter<EventsCursorStatus>
         /// <inheritdoc />
         public override EventsCursorStatus Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, EventsCursorStatus value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(EventsCursorStatus));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(EventsCursorStatus));
         }
     }
 }
@@ -9837,13 +9837,13 @@ public sealed class Converter : JsonConverter<EventsAgentScope>
         /// <inheritdoc />
         public override EventsAgentScope Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, EventsAgentScope value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(EventsAgentScope));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(EventsAgentScope));
         }
     }
 }
@@ -9903,13 +9903,13 @@ public sealed class Converter : JsonConverter<RemoteSessionMode>
         /// <inheritdoc />
         public override RemoteSessionMode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, RemoteSessionMode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(RemoteSessionMode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(RemoteSessionMode));
         }
     }
 }
@@ -9965,13 +9965,13 @@ public sealed class Converter : JsonConverter<SessionFsErrorCode>
         /// <inheritdoc />
         public override SessionFsErrorCode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SessionFsErrorCode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionFsErrorCode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionFsErrorCode));
         }
     }
 }
@@ -10027,13 +10027,13 @@ public sealed class Converter : JsonConverter<SessionFsReaddirWithTypesEntryType
         /// <inheritdoc />
         public override SessionFsReaddirWithTypesEntryType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SessionFsReaddirWithTypesEntryType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionFsReaddirWithTypesEntryType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionFsReaddirWithTypesEntryType));
         }
     }
 }
@@ -10092,13 +10092,13 @@ public sealed class Converter : JsonConverter<SessionFsSqliteQueryType>
         /// <inheritdoc />
         public override SessionFsSqliteQueryType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SessionFsSqliteQueryType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionFsSqliteQueryType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionFsSqliteQueryType));
         }
     }
 }
@@ -13087,225 +13087,225 @@ public static void RegisterClientSessionApiHandlers(JsonRpc rpc, Func<string, Cl
 [JsonSerializable(typeof(int))]
 [JsonSerializable(typeof(long))]
 [JsonSerializable(typeof(string))]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AbortData), TypeInfoPropertyName = "SessionEventsAbortData")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AbortEvent), TypeInfoPropertyName = "SessionEventsAbortEvent")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AbortReason), TypeInfoPropertyName = "SessionEventsAbortReason")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantIntentData), TypeInfoPropertyName = "SessionEventsAssistantIntentData")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantIntentEvent), TypeInfoPropertyName = "SessionEventsAssistantIntentEvent")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantMessageData), TypeInfoPropertyName = "SessionEventsAssistantMessageData")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantMessageDeltaData), TypeInfoPropertyName = "SessionEventsAssistantMessageDeltaData")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantMessageDeltaEvent), TypeInfoPropertyName = "SessionEventsAssistantMessageDeltaEvent")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantMessageEvent), TypeInfoPropertyName = "SessionEventsAssistantMessageEvent")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantMessageStartData), TypeInfoPropertyName = "SessionEventsAssistantMessageStartData")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantMessageStartEvent), TypeInfoPropertyName = "SessionEventsAssistantMessageStartEvent")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantMessageToolRequest), TypeInfoPropertyName = "SessionEventsAssistantMessageToolRequest")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantMessageToolRequestType), TypeInfoPropertyName = "SessionEventsAssistantMessageToolRequestType")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantReasoningData), TypeInfoPropertyName = "SessionEventsAssistantReasoningData")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantReasoningDeltaData), TypeInfoPropertyName = "SessionEventsAssistantReasoningDeltaData")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantReasoningDeltaEvent), TypeInfoPropertyName = "SessionEventsAssistantReasoningDeltaEvent")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantReasoningEvent), TypeInfoPropertyName = "SessionEventsAssistantReasoningEvent")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantStreamingDeltaData), TypeInfoPropertyName = "SessionEventsAssistantStreamingDeltaData")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantStreamingDeltaEvent), TypeInfoPropertyName = "SessionEventsAssistantStreamingDeltaEvent")]
-[JsonSerializable(typeof(GitHub.Copilot.SDK.AssistantTurnEndData), TypeInfoPropertyName = "SessionEventsAssistantTurnEndData")]
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-[JsonSerializable(typeof(GitHub.Copilot.SDK.WorkspaceFileChangedOperation), TypeInfoPropertyName = "SessionEventsWorkspaceFileChangedOperation")]
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+[JsonSerializable(typeof(GitHub.Copilot.AbortEvent), TypeInfoPropertyName = "SessionEventsAbortEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.AbortReason), TypeInfoPropertyName = "SessionEventsAbortReason")]
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+[JsonSerializable(typeof(GitHub.Copilot.AssistantTurnStartData), TypeInfoPropertyName = "SessionEventsAssistantTurnStartData")]
+[JsonSerializable(typeof(GitHub.Copilot.AssistantTurnStartEvent), TypeInfoPropertyName = "SessionEventsAssistantTurnStartEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.AssistantUsageApiEndpoint), TypeInfoPropertyName = "SessionEventsAssistantUsageApiEndpoint")]
+[JsonSerializable(typeof(GitHub.Copilot.AssistantUsageCopilotUsage), TypeInfoPropertyName = "SessionEventsAssistantUsageCopilotUsage")]
+[JsonSerializable(typeof(GitHub.Copilot.AssistantUsageCopilotUsageTokenDetail), TypeInfoPropertyName = "SessionEventsAssistantUsageCopilotUsageTokenDetail")]
+[JsonSerializable(typeof(GitHub.Copilot.AssistantUsageData), TypeInfoPropertyName = "SessionEventsAssistantUsageData")]
+[JsonSerializable(typeof(GitHub.Copilot.AssistantUsageEvent), TypeInfoPropertyName = "SessionEventsAssistantUsageEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.AssistantUsageQuotaSnapshot), TypeInfoPropertyName = "SessionEventsAssistantUsageQuotaSnapshot")]
+[JsonSerializable(typeof(GitHub.Copilot.AutoModeSwitchCompletedData), TypeInfoPropertyName = "SessionEventsAutoModeSwitchCompletedData")]
+[JsonSerializable(typeof(GitHub.Copilot.AutoModeSwitchCompletedEvent), TypeInfoPropertyName = "SessionEventsAutoModeSwitchCompletedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.AutoModeSwitchRequestedData), TypeInfoPropertyName = "SessionEventsAutoModeSwitchRequestedData")]
+[JsonSerializable(typeof(GitHub.Copilot.AutoModeSwitchRequestedEvent), TypeInfoPropertyName = "SessionEventsAutoModeSwitchRequestedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.AutoModeSwitchResponse), TypeInfoPropertyName = "SessionEventsAutoModeSwitchResponse")]
+[JsonSerializable(typeof(GitHub.Copilot.CapabilitiesChangedData), TypeInfoPropertyName = "SessionEventsCapabilitiesChangedData")]
+[JsonSerializable(typeof(GitHub.Copilot.CapabilitiesChangedEvent), TypeInfoPropertyName = "SessionEventsCapabilitiesChangedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.CapabilitiesChangedUI), TypeInfoPropertyName = "SessionEventsCapabilitiesChangedUI")]
+[JsonSerializable(typeof(GitHub.Copilot.CommandCompletedData), TypeInfoPropertyName = "SessionEventsCommandCompletedData")]
+[JsonSerializable(typeof(GitHub.Copilot.CommandCompletedEvent), TypeInfoPropertyName = "SessionEventsCommandCompletedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.CommandExecuteData), TypeInfoPropertyName = "SessionEventsCommandExecuteData")]
+[JsonSerializable(typeof(GitHub.Copilot.CommandExecuteEvent), TypeInfoPropertyName = "SessionEventsCommandExecuteEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.CommandQueuedData), TypeInfoPropertyName = "SessionEventsCommandQueuedData")]
+[JsonSerializable(typeof(GitHub.Copilot.CommandQueuedEvent), TypeInfoPropertyName = "SessionEventsCommandQueuedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.CommandsChangedCommand), TypeInfoPropertyName = "SessionEventsCommandsChangedCommand")]
+[JsonSerializable(typeof(GitHub.Copilot.CommandsChangedData), TypeInfoPropertyName = "SessionEventsCommandsChangedData")]
+[JsonSerializable(typeof(GitHub.Copilot.CommandsChangedEvent), TypeInfoPropertyName = "SessionEventsCommandsChangedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.CompactionCompleteCompactionTokensUsed), TypeInfoPropertyName = "SessionEventsCompactionCompleteCompactionTokensUsed")]
+[JsonSerializable(typeof(GitHub.Copilot.CompactionCompleteCompactionTokensUsedCopilotUsage), TypeInfoPropertyName = "SessionEventsCompactionCompleteCompactionTokensUsedCopilotUsage")]
+[JsonSerializable(typeof(GitHub.Copilot.CompactionCompleteCompactionTokensUsedCopilotUsageTokenDetail), TypeInfoPropertyName = "SessionEventsCompactionCompleteCompactionTokensUsedCopilotUsageTokenDetail")]
+[JsonSerializable(typeof(GitHub.Copilot.CustomAgentsUpdatedAgent), TypeInfoPropertyName = "SessionEventsCustomAgentsUpdatedAgent")]
+[JsonSerializable(typeof(GitHub.Copilot.ElicitationCompletedAction), TypeInfoPropertyName = "SessionEventsElicitationCompletedAction")]
+[JsonSerializable(typeof(GitHub.Copilot.ElicitationCompletedData), TypeInfoPropertyName = "SessionEventsElicitationCompletedData")]
+[JsonSerializable(typeof(GitHub.Copilot.ElicitationCompletedEvent), TypeInfoPropertyName = "SessionEventsElicitationCompletedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.ElicitationRequestedData), TypeInfoPropertyName = "SessionEventsElicitationRequestedData")]
+[JsonSerializable(typeof(GitHub.Copilot.ElicitationRequestedEvent), TypeInfoPropertyName = "SessionEventsElicitationRequestedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.ElicitationRequestedMode), TypeInfoPropertyName = "SessionEventsElicitationRequestedMode")]
+[JsonSerializable(typeof(GitHub.Copilot.ElicitationRequestedSchema), TypeInfoPropertyName = "SessionEventsElicitationRequestedSchema")]
+[JsonSerializable(typeof(GitHub.Copilot.EmbeddedBlobResourceContents), TypeInfoPropertyName = "SessionEventsEmbeddedBlobResourceContents")]
+[JsonSerializable(typeof(GitHub.Copilot.EmbeddedTextResourceContents), TypeInfoPropertyName = "SessionEventsEmbeddedTextResourceContents")]
+[JsonSerializable(typeof(GitHub.Copilot.ExitPlanModeAction), TypeInfoPropertyName = "SessionEventsExitPlanModeAction")]
+[JsonSerializable(typeof(GitHub.Copilot.ExitPlanModeCompletedData), TypeInfoPropertyName = "SessionEventsExitPlanModeCompletedData")]
+[JsonSerializable(typeof(GitHub.Copilot.ExitPlanModeCompletedEvent), TypeInfoPropertyName = "SessionEventsExitPlanModeCompletedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.ExitPlanModeRequestedData), TypeInfoPropertyName = "SessionEventsExitPlanModeRequestedData")]
+[JsonSerializable(typeof(GitHub.Copilot.ExitPlanModeRequestedEvent), TypeInfoPropertyName = "SessionEventsExitPlanModeRequestedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.ExtensionsLoadedExtension), TypeInfoPropertyName = "SessionEventsExtensionsLoadedExtension")]
+[JsonSerializable(typeof(GitHub.Copilot.ExtensionsLoadedExtensionSource), TypeInfoPropertyName = "SessionEventsExtensionsLoadedExtensionSource")]
+[JsonSerializable(typeof(GitHub.Copilot.ExtensionsLoadedExtensionStatus), TypeInfoPropertyName = "SessionEventsExtensionsLoadedExtensionStatus")]
+[JsonSerializable(typeof(GitHub.Copilot.ExternalToolCompletedData), TypeInfoPropertyName = "SessionEventsExternalToolCompletedData")]
+[JsonSerializable(typeof(GitHub.Copilot.ExternalToolCompletedEvent), TypeInfoPropertyName = "SessionEventsExternalToolCompletedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.ExternalToolRequestedData), TypeInfoPropertyName = "SessionEventsExternalToolRequestedData")]
+[JsonSerializable(typeof(GitHub.Copilot.ExternalToolRequestedEvent), TypeInfoPropertyName = "SessionEventsExternalToolRequestedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.HandoffRepository), TypeInfoPropertyName = "SessionEventsHandoffRepository")]
+[JsonSerializable(typeof(GitHub.Copilot.HandoffSourceType), TypeInfoPropertyName = "SessionEventsHandoffSourceType")]
+[JsonSerializable(typeof(GitHub.Copilot.HookEndData), TypeInfoPropertyName = "SessionEventsHookEndData")]
+[JsonSerializable(typeof(GitHub.Copilot.HookEndError), TypeInfoPropertyName = "SessionEventsHookEndError")]
+[JsonSerializable(typeof(GitHub.Copilot.HookEndEvent), TypeInfoPropertyName = "SessionEventsHookEndEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.HookStartData), TypeInfoPropertyName = "SessionEventsHookStartData")]
+[JsonSerializable(typeof(GitHub.Copilot.HookStartEvent), TypeInfoPropertyName = "SessionEventsHookStartEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.McpOauthCompletedData), TypeInfoPropertyName = "SessionEventsMcpOauthCompletedData")]
+[JsonSerializable(typeof(GitHub.Copilot.McpOauthCompletedEvent), TypeInfoPropertyName = "SessionEventsMcpOauthCompletedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.McpOauthRequiredData), TypeInfoPropertyName = "SessionEventsMcpOauthRequiredData")]
+[JsonSerializable(typeof(GitHub.Copilot.McpOauthRequiredEvent), TypeInfoPropertyName = "SessionEventsMcpOauthRequiredEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.McpOauthRequiredStaticClientConfig), TypeInfoPropertyName = "SessionEventsMcpOauthRequiredStaticClientConfig")]
+[JsonSerializable(typeof(GitHub.Copilot.McpServerSource), TypeInfoPropertyName = "SessionEventsMcpServerSource")]
+[JsonSerializable(typeof(GitHub.Copilot.McpServerStatus), TypeInfoPropertyName = "SessionEventsMcpServerStatus")]
+[JsonSerializable(typeof(GitHub.Copilot.McpServersLoadedServer), TypeInfoPropertyName = "SessionEventsMcpServersLoadedServer")]
+[JsonSerializable(typeof(GitHub.Copilot.ModelCallFailureData), TypeInfoPropertyName = "SessionEventsModelCallFailureData")]
+[JsonSerializable(typeof(GitHub.Copilot.ModelCallFailureEvent), TypeInfoPropertyName = "SessionEventsModelCallFailureEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.ModelCallFailureSource), TypeInfoPropertyName = "SessionEventsModelCallFailureSource")]
+[JsonSerializable(typeof(GitHub.Copilot.PendingMessagesModifiedData), TypeInfoPropertyName = "SessionEventsPendingMessagesModifiedData")]
+[JsonSerializable(typeof(GitHub.Copilot.PendingMessagesModifiedEvent), TypeInfoPropertyName = "SessionEventsPendingMessagesModifiedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionCompletedData), TypeInfoPropertyName = "SessionEventsPermissionCompletedData")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionCompletedEvent), TypeInfoPropertyName = "SessionEventsPermissionCompletedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequest), TypeInfoPropertyName = "SessionEventsPermissionPromptRequest")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestCommands), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestCommands")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestCustomTool), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestCustomTool")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestExtensionManagement), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestExtensionManagement")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestExtensionPermissionAccess), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestExtensionPermissionAccess")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestHook), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestHook")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestMcp), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestMcp")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestMemory), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestMemory")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestPath), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestPath")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestPathAccessKind), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestPathAccessKind")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestRead), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestRead")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestUrl), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestUrl")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionPromptRequestWrite), TypeInfoPropertyName = "SessionEventsPermissionPromptRequestWrite")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequest), TypeInfoPropertyName = "SessionEventsPermissionRequest")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestCustomTool), TypeInfoPropertyName = "SessionEventsPermissionRequestCustomTool")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestExtensionManagement), TypeInfoPropertyName = "SessionEventsPermissionRequestExtensionManagement")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestExtensionPermissionAccess), TypeInfoPropertyName = "SessionEventsPermissionRequestExtensionPermissionAccess")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestHook), TypeInfoPropertyName = "SessionEventsPermissionRequestHook")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestMcp), TypeInfoPropertyName = "SessionEventsPermissionRequestMcp")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestMemory), TypeInfoPropertyName = "SessionEventsPermissionRequestMemory")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestMemoryAction), TypeInfoPropertyName = "SessionEventsPermissionRequestMemoryAction")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestMemoryDirection), TypeInfoPropertyName = "SessionEventsPermissionRequestMemoryDirection")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestRead), TypeInfoPropertyName = "SessionEventsPermissionRequestRead")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestShell), TypeInfoPropertyName = "SessionEventsPermissionRequestShell")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestShellCommand), TypeInfoPropertyName = "SessionEventsPermissionRequestShellCommand")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestShellPossibleUrl), TypeInfoPropertyName = "SessionEventsPermissionRequestShellPossibleUrl")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestUrl), TypeInfoPropertyName = "SessionEventsPermissionRequestUrl")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestWrite), TypeInfoPropertyName = "SessionEventsPermissionRequestWrite")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestedData), TypeInfoPropertyName = "SessionEventsPermissionRequestedData")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRequestedEvent), TypeInfoPropertyName = "SessionEventsPermissionRequestedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionResult), TypeInfoPropertyName = "SessionEventsPermissionResult")]
+[JsonSerializable(typeof(GitHub.Copilot.PermissionRule), TypeInfoPropertyName = "SessionEventsPermissionRule")]
+[JsonSerializable(typeof(GitHub.Copilot.PlanChangedOperation), TypeInfoPropertyName = "SessionEventsPlanChangedOperation")]
+[JsonSerializable(typeof(GitHub.Copilot.ReasoningSummary), TypeInfoPropertyName = "SessionEventsReasoningSummary")]
+[JsonSerializable(typeof(GitHub.Copilot.SamplingCompletedData), TypeInfoPropertyName = "SessionEventsSamplingCompletedData")]
+[JsonSerializable(typeof(GitHub.Copilot.SamplingCompletedEvent), TypeInfoPropertyName = "SessionEventsSamplingCompletedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SamplingRequestedData), TypeInfoPropertyName = "SessionEventsSamplingRequestedData")]
+[JsonSerializable(typeof(GitHub.Copilot.SamplingRequestedEvent), TypeInfoPropertyName = "SessionEventsSamplingRequestedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SessionEvent), TypeInfoPropertyName = "SessionEventsSessionEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SessionMode), TypeInfoPropertyName = "SessionEventsSessionMode")]
+[JsonSerializable(typeof(GitHub.Copilot.ShutdownCodeChanges), TypeInfoPropertyName = "SessionEventsShutdownCodeChanges")]
+[JsonSerializable(typeof(GitHub.Copilot.ShutdownModelMetric), TypeInfoPropertyName = "SessionEventsShutdownModelMetric")]
+[JsonSerializable(typeof(GitHub.Copilot.ShutdownModelMetricRequests), TypeInfoPropertyName = "SessionEventsShutdownModelMetricRequests")]
+[JsonSerializable(typeof(GitHub.Copilot.ShutdownModelMetricTokenDetail), TypeInfoPropertyName = "SessionEventsShutdownModelMetricTokenDetail")]
+[JsonSerializable(typeof(GitHub.Copilot.ShutdownModelMetricUsage), TypeInfoPropertyName = "SessionEventsShutdownModelMetricUsage")]
+[JsonSerializable(typeof(GitHub.Copilot.ShutdownTokenDetail), TypeInfoPropertyName = "SessionEventsShutdownTokenDetail")]
+[JsonSerializable(typeof(GitHub.Copilot.ShutdownType), TypeInfoPropertyName = "SessionEventsShutdownType")]
+[JsonSerializable(typeof(GitHub.Copilot.SkillInvokedData), TypeInfoPropertyName = "SessionEventsSkillInvokedData")]
+[JsonSerializable(typeof(GitHub.Copilot.SkillInvokedEvent), TypeInfoPropertyName = "SessionEventsSkillInvokedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SkillSource), TypeInfoPropertyName = "SessionEventsSkillSource")]
+[JsonSerializable(typeof(GitHub.Copilot.SkillsLoadedSkill), TypeInfoPropertyName = "SessionEventsSkillsLoadedSkill")]
+[JsonSerializable(typeof(GitHub.Copilot.SubagentCompletedData), TypeInfoPropertyName = "SessionEventsSubagentCompletedData")]
+[JsonSerializable(typeof(GitHub.Copilot.SubagentCompletedEvent), TypeInfoPropertyName = "SessionEventsSubagentCompletedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SubagentDeselectedData), TypeInfoPropertyName = "SessionEventsSubagentDeselectedData")]
+[JsonSerializable(typeof(GitHub.Copilot.SubagentDeselectedEvent), TypeInfoPropertyName = "SessionEventsSubagentDeselectedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SubagentFailedData), TypeInfoPropertyName = "SessionEventsSubagentFailedData")]
+[JsonSerializable(typeof(GitHub.Copilot.SubagentFailedEvent), TypeInfoPropertyName = "SessionEventsSubagentFailedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SubagentSelectedData), TypeInfoPropertyName = "SessionEventsSubagentSelectedData")]
+[JsonSerializable(typeof(GitHub.Copilot.SubagentSelectedEvent), TypeInfoPropertyName = "SessionEventsSubagentSelectedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SubagentStartedData), TypeInfoPropertyName = "SessionEventsSubagentStartedData")]
+[JsonSerializable(typeof(GitHub.Copilot.SubagentStartedEvent), TypeInfoPropertyName = "SessionEventsSubagentStartedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemMessageData), TypeInfoPropertyName = "SessionEventsSystemMessageData")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemMessageEvent), TypeInfoPropertyName = "SessionEventsSystemMessageEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemMessageMetadata), TypeInfoPropertyName = "SessionEventsSystemMessageMetadata")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemMessageRole), TypeInfoPropertyName = "SessionEventsSystemMessageRole")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemNotification), TypeInfoPropertyName = "SessionEventsSystemNotification")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemNotificationAgentCompleted), TypeInfoPropertyName = "SessionEventsSystemNotificationAgentCompleted")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemNotificationAgentCompletedStatus), TypeInfoPropertyName = "SessionEventsSystemNotificationAgentCompletedStatus")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemNotificationAgentIdle), TypeInfoPropertyName = "SessionEventsSystemNotificationAgentIdle")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemNotificationData), TypeInfoPropertyName = "SessionEventsSystemNotificationData")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemNotificationEvent), TypeInfoPropertyName = "SessionEventsSystemNotificationEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemNotificationInstructionDiscovered), TypeInfoPropertyName = "SessionEventsSystemNotificationInstructionDiscovered")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemNotificationNewInboxMessage), TypeInfoPropertyName = "SessionEventsSystemNotificationNewInboxMessage")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemNotificationShellCompleted), TypeInfoPropertyName = "SessionEventsSystemNotificationShellCompleted")]
+[JsonSerializable(typeof(GitHub.Copilot.SystemNotificationShellDetachedCompleted), TypeInfoPropertyName = "SessionEventsSystemNotificationShellDetachedCompleted")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteContent), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteContent")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteContentAudio), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteContentAudio")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteContentImage), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteContentImage")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteContentResource), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteContentResource")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteContentResourceDetails), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteContentResourceDetails")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteContentResourceLink), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteContentResourceLink")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteContentResourceLinkIcon), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteContentResourceLinkIcon")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteContentResourceLinkIconTheme), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteContentResourceLinkIconTheme")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteContentTerminal), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteContentTerminal")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteContentText), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteContentText")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteData), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteData")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteError), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteError")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteEvent), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionCompleteResult), TypeInfoPropertyName = "SessionEventsToolExecutionCompleteResult")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionPartialResultEvent), TypeInfoPropertyName = "SessionEventsToolExecutionPartialResultEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionProgressData), TypeInfoPropertyName = "SessionEventsToolExecutionProgressData")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionProgressEvent), TypeInfoPropertyName = "SessionEventsToolExecutionProgressEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionStartData), TypeInfoPropertyName = "SessionEventsToolExecutionStartData")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolExecutionStartEvent), TypeInfoPropertyName = "SessionEventsToolExecutionStartEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolUserRequestedData), TypeInfoPropertyName = "SessionEventsToolUserRequestedData")]
+[JsonSerializable(typeof(GitHub.Copilot.ToolUserRequestedEvent), TypeInfoPropertyName = "SessionEventsToolUserRequestedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.UserInputCompletedData), TypeInfoPropertyName = "SessionEventsUserInputCompletedData")]
+[JsonSerializable(typeof(GitHub.Copilot.UserInputCompletedEvent), TypeInfoPropertyName = "SessionEventsUserInputCompletedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.UserInputRequestedData), TypeInfoPropertyName = "SessionEventsUserInputRequestedData")]
+[JsonSerializable(typeof(GitHub.Copilot.UserInputRequestedEvent), TypeInfoPropertyName = "SessionEventsUserInputRequestedEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAgentMode), TypeInfoPropertyName = "SessionEventsUserMessageAgentMode")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachment), TypeInfoPropertyName = "SessionEventsUserMessageAttachment")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachmentBlob), TypeInfoPropertyName = "SessionEventsUserMessageAttachmentBlob")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachmentDirectory), TypeInfoPropertyName = "SessionEventsUserMessageAttachmentDirectory")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachmentFile), TypeInfoPropertyName = "SessionEventsUserMessageAttachmentFile")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachmentFileLineRange), TypeInfoPropertyName = "SessionEventsUserMessageAttachmentFileLineRange")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachmentGithubReference), TypeInfoPropertyName = "SessionEventsUserMessageAttachmentGithubReference")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachmentGithubReferenceType), TypeInfoPropertyName = "SessionEventsUserMessageAttachmentGithubReferenceType")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachmentSelection), TypeInfoPropertyName = "SessionEventsUserMessageAttachmentSelection")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachmentSelectionDetails), TypeInfoPropertyName = "SessionEventsUserMessageAttachmentSelectionDetails")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachmentSelectionDetailsEnd), TypeInfoPropertyName = "SessionEventsUserMessageAttachmentSelectionDetailsEnd")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageAttachmentSelectionDetailsStart), TypeInfoPropertyName = "SessionEventsUserMessageAttachmentSelectionDetailsStart")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageData), TypeInfoPropertyName = "SessionEventsUserMessageData")]
+[JsonSerializable(typeof(GitHub.Copilot.UserMessageEvent), TypeInfoPropertyName = "SessionEventsUserMessageEvent")]
+[JsonSerializable(typeof(GitHub.Copilot.UserToolSessionApproval), TypeInfoPropertyName = "SessionEventsUserToolSessionApproval")]
+[JsonSerializable(typeof(GitHub.Copilot.UserToolSessionApprovalCommands), TypeInfoPropertyName = "SessionEventsUserToolSessionApprovalCommands")]
+[JsonSerializable(typeof(GitHub.Copilot.UserToolSessionApprovalCustomTool), TypeInfoPropertyName = "SessionEventsUserToolSessionApprovalCustomTool")]
+[JsonSerializable(typeof(GitHub.Copilot.UserToolSessionApprovalExtensionManagement), TypeInfoPropertyName = "SessionEventsUserToolSessionApprovalExtensionManagement")]
+[JsonSerializable(typeof(GitHub.Copilot.UserToolSessionApprovalExtensionPermissionAccess), TypeInfoPropertyName = "SessionEventsUserToolSessionApprovalExtensionPermissionAccess")]
+[JsonSerializable(typeof(GitHub.Copilot.UserToolSessionApprovalMcp), TypeInfoPropertyName = "SessionEventsUserToolSessionApprovalMcp")]
+[JsonSerializable(typeof(GitHub.Copilot.UserToolSessionApprovalMemory), TypeInfoPropertyName = "SessionEventsUserToolSessionApprovalMemory")]
+[JsonSerializable(typeof(GitHub.Copilot.UserToolSessionApprovalRead), TypeInfoPropertyName = "SessionEventsUserToolSessionApprovalRead")]
+[JsonSerializable(typeof(GitHub.Copilot.UserToolSessionApprovalWrite), TypeInfoPropertyName = "SessionEventsUserToolSessionApprovalWrite")]
+[JsonSerializable(typeof(GitHub.Copilot.WorkingDirectoryContext), TypeInfoPropertyName = "SessionEventsWorkingDirectoryContext")]
+[JsonSerializable(typeof(GitHub.Copilot.WorkingDirectoryContextHostType), TypeInfoPropertyName = "SessionEventsWorkingDirectoryContextHostType")]
+[JsonSerializable(typeof(GitHub.Copilot.WorkspaceFileChangedOperation), TypeInfoPropertyName = "SessionEventsWorkspaceFileChangedOperation")]
 [JsonSerializable(typeof(AbortRequest))]
 [JsonSerializable(typeof(AbortResult))]
 [JsonSerializable(typeof(AccountGetQuotaRequest))]
diff --git a/dotnet/src/Generated/SessionEvents.cs b/dotnet/src/Generated/SessionEvents.cs
index c5a00b5d6..b0db5de05 100644
--- a/dotnet/src/Generated/SessionEvents.cs
+++ b/dotnet/src/Generated/SessionEvents.cs
@@ -15,7 +15,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 /// <summary>
 /// Provides the base class from which all session events derive.
@@ -5345,13 +5345,13 @@ public sealed class Converter : JsonConverter<WorkingDirectoryContextHostType>
         /// <inheritdoc />
         public override WorkingDirectoryContextHostType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, WorkingDirectoryContextHostType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(WorkingDirectoryContextHostType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(WorkingDirectoryContextHostType));
         }
     }
 }
@@ -5409,13 +5409,13 @@ public sealed class Converter : JsonConverter<ReasoningSummary>
         /// <inheritdoc />
         public override ReasoningSummary Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ReasoningSummary value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ReasoningSummary));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ReasoningSummary));
         }
     }
 }
@@ -5473,13 +5473,13 @@ public sealed class Converter : JsonConverter<SessionMode>
         /// <inheritdoc />
         public override SessionMode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SessionMode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionMode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SessionMode));
         }
     }
 }
@@ -5537,13 +5537,13 @@ public sealed class Converter : JsonConverter<PlanChangedOperation>
         /// <inheritdoc />
         public override PlanChangedOperation Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, PlanChangedOperation value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PlanChangedOperation));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PlanChangedOperation));
         }
     }
 }
@@ -5598,13 +5598,13 @@ public sealed class Converter : JsonConverter<WorkspaceFileChangedOperation>
         /// <inheritdoc />
         public override WorkspaceFileChangedOperation Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, WorkspaceFileChangedOperation value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(WorkspaceFileChangedOperation));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(WorkspaceFileChangedOperation));
         }
     }
 }
@@ -5659,13 +5659,13 @@ public sealed class Converter : JsonConverter<HandoffSourceType>
         /// <inheritdoc />
         public override HandoffSourceType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, HandoffSourceType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(HandoffSourceType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(HandoffSourceType));
         }
     }
 }
@@ -5720,13 +5720,13 @@ public sealed class Converter : JsonConverter<ShutdownType>
         /// <inheritdoc />
         public override ShutdownType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ShutdownType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ShutdownType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ShutdownType));
         }
     }
 }
@@ -5787,13 +5787,13 @@ public sealed class Converter : JsonConverter<UserMessageAgentMode>
         /// <inheritdoc />
         public override UserMessageAgentMode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, UserMessageAgentMode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(UserMessageAgentMode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(UserMessageAgentMode));
         }
     }
 }
@@ -5851,13 +5851,13 @@ public sealed class Converter : JsonConverter<UserMessageAttachmentGithubReferen
         /// <inheritdoc />
         public override UserMessageAttachmentGithubReferenceType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, UserMessageAttachmentGithubReferenceType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(UserMessageAttachmentGithubReferenceType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(UserMessageAttachmentGithubReferenceType));
         }
     }
 }
@@ -5912,13 +5912,13 @@ public sealed class Converter : JsonConverter<AssistantMessageToolRequestType>
         /// <inheritdoc />
         public override AssistantMessageToolRequestType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, AssistantMessageToolRequestType value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AssistantMessageToolRequestType));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AssistantMessageToolRequestType));
         }
     }
 }
@@ -5979,13 +5979,13 @@ public sealed class Converter : JsonConverter<AssistantUsageApiEndpoint>
         /// <inheritdoc />
         public override AssistantUsageApiEndpoint Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, AssistantUsageApiEndpoint value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AssistantUsageApiEndpoint));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AssistantUsageApiEndpoint));
         }
     }
 }
@@ -6043,13 +6043,13 @@ public sealed class Converter : JsonConverter<ModelCallFailureSource>
         /// <inheritdoc />
         public override ModelCallFailureSource Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ModelCallFailureSource value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ModelCallFailureSource));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ModelCallFailureSource));
         }
     }
 }
@@ -6107,13 +6107,13 @@ public sealed class Converter : JsonConverter<AbortReason>
         /// <inheritdoc />
         public override AbortReason Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, AbortReason value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AbortReason));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AbortReason));
         }
     }
 }
@@ -6168,13 +6168,13 @@ public sealed class Converter : JsonConverter<ToolExecutionCompleteContentResour
         /// <inheritdoc />
         public override ToolExecutionCompleteContentResourceLinkIconTheme Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ToolExecutionCompleteContentResourceLinkIconTheme value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ToolExecutionCompleteContentResourceLinkIconTheme));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ToolExecutionCompleteContentResourceLinkIconTheme));
         }
     }
 }
@@ -6229,13 +6229,13 @@ public sealed class Converter : JsonConverter<SystemMessageRole>
         /// <inheritdoc />
         public override SystemMessageRole Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SystemMessageRole value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SystemMessageRole));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SystemMessageRole));
         }
     }
 }
@@ -6290,13 +6290,13 @@ public sealed class Converter : JsonConverter<SystemNotificationAgentCompletedSt
         /// <inheritdoc />
         public override SystemNotificationAgentCompletedStatus Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SystemNotificationAgentCompletedStatus value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SystemNotificationAgentCompletedStatus));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SystemNotificationAgentCompletedStatus));
         }
     }
 }
@@ -6351,13 +6351,13 @@ public sealed class Converter : JsonConverter<PermissionRequestMemoryAction>
         /// <inheritdoc />
         public override PermissionRequestMemoryAction Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, PermissionRequestMemoryAction value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionRequestMemoryAction));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionRequestMemoryAction));
         }
     }
 }
@@ -6412,13 +6412,13 @@ public sealed class Converter : JsonConverter<PermissionRequestMemoryDirection>
         /// <inheritdoc />
         public override PermissionRequestMemoryDirection Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, PermissionRequestMemoryDirection value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionRequestMemoryDirection));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionRequestMemoryDirection));
         }
     }
 }
@@ -6476,13 +6476,13 @@ public sealed class Converter : JsonConverter<PermissionPromptRequestPathAccessK
         /// <inheritdoc />
         public override PermissionPromptRequestPathAccessKind Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, PermissionPromptRequestPathAccessKind value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionPromptRequestPathAccessKind));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(PermissionPromptRequestPathAccessKind));
         }
     }
 }
@@ -6537,13 +6537,13 @@ public sealed class Converter : JsonConverter<ElicitationRequestedMode>
         /// <inheritdoc />
         public override ElicitationRequestedMode Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ElicitationRequestedMode value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ElicitationRequestedMode));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ElicitationRequestedMode));
         }
     }
 }
@@ -6601,13 +6601,13 @@ public sealed class Converter : JsonConverter<ElicitationCompletedAction>
         /// <inheritdoc />
         public override ElicitationCompletedAction Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ElicitationCompletedAction value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ElicitationCompletedAction));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ElicitationCompletedAction));
         }
     }
 }
@@ -6665,13 +6665,13 @@ public sealed class Converter : JsonConverter<AutoModeSwitchResponse>
         /// <inheritdoc />
         public override AutoModeSwitchResponse Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, AutoModeSwitchResponse value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AutoModeSwitchResponse));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(AutoModeSwitchResponse));
         }
     }
 }
@@ -6732,13 +6732,13 @@ public sealed class Converter : JsonConverter<ExitPlanModeAction>
         /// <inheritdoc />
         public override ExitPlanModeAction Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ExitPlanModeAction value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ExitPlanModeAction));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ExitPlanModeAction));
         }
     }
 }
@@ -6808,13 +6808,13 @@ public sealed class Converter : JsonConverter<SkillSource>
         /// <inheritdoc />
         public override SkillSource Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, SkillSource value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SkillSource));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(SkillSource));
         }
     }
 }
@@ -6875,13 +6875,13 @@ public sealed class Converter : JsonConverter<McpServerSource>
         /// <inheritdoc />
         public override McpServerSource Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, McpServerSource value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(McpServerSource));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(McpServerSource));
         }
     }
 }
@@ -6948,13 +6948,13 @@ public sealed class Converter : JsonConverter<McpServerStatus>
         /// <inheritdoc />
         public override McpServerStatus Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, McpServerStatus value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(McpServerStatus));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(McpServerStatus));
         }
     }
 }
@@ -7009,13 +7009,13 @@ public sealed class Converter : JsonConverter<ExtensionsLoadedExtensionSource>
         /// <inheritdoc />
         public override ExtensionsLoadedExtensionSource Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ExtensionsLoadedExtensionSource value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ExtensionsLoadedExtensionSource));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ExtensionsLoadedExtensionSource));
         }
     }
 }
@@ -7076,13 +7076,13 @@ public sealed class Converter : JsonConverter<ExtensionsLoadedExtensionStatus>
         /// <inheritdoc />
         public override ExtensionsLoadedExtensionStatus Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
+            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));
         }
 
         /// <inheritdoc />
         public override void Write(Utf8JsonWriter writer, ExtensionsLoadedExtensionStatus value, JsonSerializerOptions options)
         {
-            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ExtensionsLoadedExtensionStatus));
+            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(ExtensionsLoadedExtensionStatus));
         }
     }
 }
diff --git a/dotnet/src/GitHub.Copilot.SDK.csproj b/dotnet/src/GitHub.Copilot.SDK.csproj
index 933b51de2..2b69cbb6f 100644
--- a/dotnet/src/GitHub.Copilot.SDK.csproj
+++ b/dotnet/src/GitHub.Copilot.SDK.csproj
@@ -2,8 +2,9 @@
 
     <PropertyGroup>
         <TargetFrameworks>net8.0;net10.0;netstandard2.0</TargetFrameworks>
+        <RootNamespace>GitHub.Copilot</RootNamespace>
         <GenerateDocumentationFile>true</GenerateDocumentationFile>
-        <Version>0.1.0</Version>
+        <Version>0.0.0-dev</Version>
         <Description>SDK for programmatic control of GitHub Copilot CLI</Description>
         <Authors>GitHub</Authors>
         <Company>GitHub</Company>
diff --git a/dotnet/src/JsonRpc.cs b/dotnet/src/JsonRpc.cs
index a97d0baed..866bb868f 100644
--- a/dotnet/src/JsonRpc.cs
+++ b/dotnet/src/JsonRpc.cs
@@ -14,7 +14,7 @@
 using System.Text.Json.Serialization.Metadata;
 using System.Text.Unicode;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 /// <summary>
 /// A lightweight JSON-RPC 2.0 implementation covering only the features used
diff --git a/dotnet/src/LoggingHelpers.cs b/dotnet/src/LoggingHelpers.cs
index ca14ea3b9..a4f51cb65 100644
--- a/dotnet/src/LoggingHelpers.cs
+++ b/dotnet/src/LoggingHelpers.cs
@@ -5,7 +5,7 @@
 using Microsoft.Extensions.Logging;
 using System.Diagnostics;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 internal static class LoggingHelpers
 {
diff --git a/dotnet/src/MillisecondsTimeSpanConverter.cs b/dotnet/src/MillisecondsTimeSpanConverter.cs
index 696d053dd..738d68648 100644
--- a/dotnet/src/MillisecondsTimeSpanConverter.cs
+++ b/dotnet/src/MillisecondsTimeSpanConverter.cs
@@ -6,7 +6,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 /// <summary>Converts between JSON numeric milliseconds and <see cref="TimeSpan"/>.</summary>
 [EditorBrowsable(EditorBrowsableState.Never)]
diff --git a/dotnet/src/PermissionHandlers.cs b/dotnet/src/PermissionHandlers.cs
index 3a40e7244..0e4af7eac 100644
--- a/dotnet/src/PermissionHandlers.cs
+++ b/dotnet/src/PermissionHandlers.cs
@@ -2,12 +2,12 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
-/// <summary>Provides pre-built <see cref="PermissionRequestHandler"/> implementations.</summary>
+/// <summary>Provides pre-built permission request handlers.</summary>
 public static class PermissionHandler
 {
-    /// <summary>A <see cref="PermissionRequestHandler"/> that approves all permission requests.</summary>
-    public static PermissionRequestHandler ApproveAll { get; } =
+    /// <summary>A permission handler that approves all permission requests.</summary>
+    public static Func<PermissionRequest, PermissionInvocation, Task<PermissionRequestResult>> ApproveAll { get; } =
         (_, _) => Task.FromResult(new PermissionRequestResult { Kind = PermissionRequestResultKind.Approved });
 }
diff --git a/dotnet/src/SdkProtocolVersion.cs b/dotnet/src/SdkProtocolVersion.cs
index 889af460b..659387b79 100644
--- a/dotnet/src/SdkProtocolVersion.cs
+++ b/dotnet/src/SdkProtocolVersion.cs
@@ -1,6 +1,6 @@
 // Code generated by update-protocol-version.ts. DO NOT EDIT.
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 /// <summary>
 /// Provides the SDK protocol version.
diff --git a/dotnet/src/Session.cs b/dotnet/src/Session.cs
index 1ca9eb621..fc7d82675 100644
--- a/dotnet/src/Session.cs
+++ b/dotnet/src/Session.cs
@@ -1,8 +1,8 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
+using GitHub.Copilot.Rpc;
 using Microsoft.Extensions.AI;
 using Microsoft.Extensions.Logging;
 using System.Collections.Immutable;
@@ -12,7 +12,7 @@
 using System.Text.Json.Serialization;
 using System.Threading.Channels;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 /// <summary>
 /// Represents a single conversation session with the Copilot CLI.
@@ -41,7 +41,7 @@ namespace GitHub.Copilot.SDK;
 /// await using var session = await client.CreateSessionAsync(new() { OnPermissionRequest = PermissionHandler.ApproveAll, Model = "gpt-4" });
 ///
 /// // Subscribe to events
-/// using var subscription = session.On(evt =>
+/// using var subscription = session.On&lt;SessionEvent&gt;(evt =&gt;
 /// {
 ///     if (evt is AssistantMessageEvent assistantMessage)
 ///     {
@@ -56,16 +56,18 @@ namespace GitHub.Copilot.SDK;
 public sealed partial class CopilotSession : IAsyncDisposable
 {
     private readonly Dictionary<string, AIFunction> _toolHandlers = [];
-    private readonly Dictionary<string, CommandHandler> _commandHandlers = [];
+    private readonly Dictionary<string, Func<CommandContext, Task>> _commandHandlers = [];
     private readonly ILogger _logger;
     private readonly CopilotClient _parentClient;
 
-    private volatile PermissionRequestHandler? _permissionHandler;
-    private volatile UserInputHandler? _userInputHandler;
-    private volatile ElicitationHandler? _elicitationHandler;
-    private volatile ExitPlanModeHandler? _exitPlanModeHandler;
-    private volatile AutoModeSwitchHandler? _autoModeSwitchHandler;
-    private ImmutableArray<SessionEventHandler> _eventHandlers = ImmutableArray<SessionEventHandler>.Empty;
+    private volatile Func<PermissionRequest, PermissionInvocation, Task<PermissionRequestResult>>? _permissionHandler;
+    private volatile Func<UserInputRequest, UserInputInvocation, Task<UserInputResponse>>? _userInputHandler;
+    private volatile Func<ElicitationContext, Task<ElicitationResult>>? _elicitationHandler;
+    private volatile Func<ExitPlanModeRequest, ExitPlanModeInvocation, Task<ExitPlanModeResult>>? _exitPlanModeHandler;
+    private volatile Func<AutoModeSwitchRequest, AutoModeSwitchInvocation, Task<AutoModeSwitchResponse>>? _autoModeSwitchHandler;
+    private ImmutableArray<EventSubscription> _eventHandlers = ImmutableArray<EventSubscription>.Empty;
+
+    private sealed record EventSubscription(Type EventType, Action<SessionEvent> Handler);
 
     private SessionHooks? _hooks;
     private readonly SemaphoreSlim _hooksLock = new(1, 1);
@@ -189,7 +191,34 @@ private Task<T> InvokeRpcAsync<T>(string method, object?[]? args, CancellationTo
     }
 
     /// <summary>
-    /// Sends a message to the Copilot session and waits for the response.
+    /// Sends a plain-text user message and returns the message ID without waiting for
+    /// the assistant to reply. Convenience overload for <see cref="SendAsync(MessageOptions, CancellationToken)"/>.
+    /// </summary>
+    /// <param name="prompt">The user message text.</param>
+    /// <param name="cancellationToken">A <see cref="CancellationToken"/> that can be used to cancel the operation.</param>
+    /// <returns>A task that resolves with the message ID.</returns>
+    public Task<string> SendAsync(string prompt, CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(prompt);
+        return SendAsync(new MessageOptions { Prompt = prompt }, cancellationToken);
+    }
+
+    /// <summary>
+    /// Sends a plain-text user message and waits until the session becomes idle.
+    /// Convenience overload for <see cref="SendAndWaitAsync(MessageOptions, TimeSpan?, CancellationToken)"/>.
+    /// </summary>
+    /// <param name="prompt">The user message text.</param>
+    /// <param name="timeout">Timeout duration (default: 60 seconds).</param>
+    /// <param name="cancellationToken">A <see cref="CancellationToken"/> that can be used to cancel the operation.</param>
+    /// <returns>A task that resolves with the final assistant message event, or null if none was received.</returns>
+    public Task<AssistantMessageEvent?> SendAndWaitAsync(string prompt, TimeSpan? timeout = null, CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(prompt);
+        return SendAndWaitAsync(new MessageOptions { Prompt = prompt }, timeout, cancellationToken);
+    }
+
+    /// <summary>
+    /// Sends a message to the Copilot session.
     /// </summary>
     /// <param name="options">Options for the message to be sent, including the prompt and optional attachments.</param>
     /// <param name="cancellationToken">A <see cref="CancellationToken"/> that can be used to cancel the operation.</param>
@@ -197,11 +226,11 @@ private Task<T> InvokeRpcAsync<T>(string method, object?[]? args, CancellationTo
     /// <exception cref="InvalidOperationException">Thrown if the session has been disposed.</exception>
     /// <remarks>
     /// <para>
-    /// This method returns immediately after the message is queued. Use <see cref="SendAndWaitAsync"/>
+    /// This method returns immediately after the message is queued. Use <see cref="SendAndWaitAsync(MessageOptions, TimeSpan?, CancellationToken)"/>
     /// if you need to wait for the assistant to finish processing.
     /// </para>
     /// <para>
-    /// Subscribe to events via <see cref="On"/> to receive streaming responses and other session events.
+    /// Subscribe to events via <see cref="On{T}"/> to receive streaming responses and other session events.
     /// </para>
     /// </remarks>
     /// <example>
@@ -258,12 +287,12 @@ public async Task<string> SendAsync(MessageOptions options, CancellationToken ca
     /// <exception cref="InvalidOperationException">Thrown if the session has been disposed.</exception>
     /// <remarks>
     /// <para>
-    /// This is a convenience method that combines <see cref="SendAsync"/> with waiting for
+    /// This is a convenience method that combines <see cref="SendAsync(MessageOptions, CancellationToken)"/> with waiting for
     /// the <c>session.idle</c> event. Use this when you want to block until the assistant
     /// has finished processing the message.
     /// </para>
     /// <para>
-    /// Events are still delivered to handlers registered via <see cref="On"/> while waiting.
+    /// Events are still delivered to handlers registered via <see cref="On{T}"/> while waiting.
     /// </para>
     /// </remarks>
     /// <example>
@@ -318,7 +347,7 @@ void Handler(SessionEvent evt)
             }
         }
 
-        using var subscription = On(Handler);
+        using var subscription = On<SessionEvent>(Handler);
 
         await SendAsync(options, cancellationToken);
 
@@ -381,7 +410,7 @@ void Handler(SessionEvent evt)
     /// </remarks>
     /// <example>
     /// <code>
-    /// using var subscription = session.On(evt =>
+    /// using var subscription = session.On&lt;SessionEvent&gt;(evt =&gt;
     /// {
     ///     switch (evt)
     ///     {
@@ -394,16 +423,21 @@ void Handler(SessionEvent evt)
     ///     }
     /// });
     ///
+    /// // Or filter to a specific event kind at compile time:
+    /// using var sub2 = session.On&lt;AssistantMessageEvent&gt;(evt =&gt;
+    ///     Console.WriteLine(evt.Data?.Content));
+    ///
     /// // The handler is automatically unsubscribed when the subscription is disposed.
     /// </code>
     /// </example>
-    public IDisposable On(SessionEventHandler handler)
+    public IDisposable On<T>(Action<T> handler) where T : SessionEvent
     {
         ArgumentNullException.ThrowIfNull(handler);
         ThrowIfDisposed();
 
-        ImmutableInterlocked.Update(ref _eventHandlers, array => array.Add(handler));
-        return new ActionDisposable(() => ImmutableInterlocked.Update(ref _eventHandlers, array => array.Remove(handler)));
+        var subscription = new EventSubscription(typeof(T), evt => handler((T)evt));
+        ImmutableInterlocked.Update(ref _eventHandlers, array => array.Add(subscription));
+        return new ActionDisposable(() => ImmutableInterlocked.Update(ref _eventHandlers, array => array.Remove(subscription)));
     }
 
     /// <summary>
@@ -438,11 +472,16 @@ private async Task ProcessEventsAsync()
         await foreach (var sessionEvent in _eventChannel.Reader.ReadAllAsync())
         {
             var dispatchTimestamp = Stopwatch.GetTimestamp();
-            foreach (var handler in _eventHandlers)
+            var eventType = sessionEvent.GetType();
+            foreach (var subscription in _eventHandlers)
             {
+                if (!subscription.EventType.IsAssignableFrom(eventType))
+                {
+                    continue;
+                }
                 try
                 {
-                    handler(sessionEvent);
+                    subscription.Handler(sessionEvent);
                 }
                 catch (Exception ex)
                 {
@@ -496,7 +535,7 @@ internal void RegisterTools(ICollection<AIFunctionDeclaration> tools)
     /// When the assistant needs permission to perform certain actions (e.g., file operations),
     /// this handler is called to approve or deny the request.
     /// </remarks>
-    internal void RegisterPermissionHandler(PermissionRequestHandler? handler)
+    internal void RegisterPermissionHandler(Func<PermissionRequest, PermissionInvocation, Task<PermissionRequestResult>>? handler)
     {
         _permissionHandler = handler;
     }
@@ -726,7 +765,7 @@ private async Task ExecuteToolAndRespondAsync(string requestId, string toolName,
     /// <summary>
     /// Executes a permission handler and sends the result back via the HandlePendingPermissionRequest RPC.
     /// </summary>
-    private async Task ExecutePermissionAndRespondAsync(string requestId, PermissionRequest permissionRequest, PermissionRequestHandler handler)
+    private async Task ExecutePermissionAndRespondAsync(string requestId, PermissionRequest permissionRequest, Func<PermissionRequest, PermissionInvocation, Task<PermissionRequestResult>> handler)
     {
         try
         {
@@ -747,7 +786,10 @@ private async Task ExecutePermissionAndRespondAsync(string requestId, Permission
                 return;
             }
             var responseRpcTimestamp = Stopwatch.GetTimestamp();
-            await Rpc.Permissions.HandlePendingPermissionRequestAsync(requestId, new PermissionDecision { Kind = result.Kind.Value });
+            PermissionDecision decision = result.Kind == PermissionRequestResultKind.Rejected
+                ? new PermissionDecisionReject { Feedback = result.Feedback }
+                : new PermissionDecision { Kind = result.Kind.Value };
+            await Rpc.Permissions.HandlePendingPermissionRequestAsync(requestId, decision);
             LoggingHelpers.LogTiming(_logger, LogLevel.Debug, null,
                 "CopilotSession.ExecutePermissionAndRespondAsync response sent successfully. Elapsed={Elapsed}, SessionId={SessionId}, RequestId={RequestId}",
                 responseRpcTimestamp,
@@ -778,7 +820,7 @@ private async Task ExecutePermissionAndRespondAsync(string requestId, Permission
     /// Registers a handler for user input requests from the agent.
     /// </summary>
     /// <param name="handler">The handler to invoke when user input is requested.</param>
-    internal void RegisterUserInputHandler(UserInputHandler handler)
+    internal void RegisterUserInputHandler(Func<UserInputRequest, UserInputInvocation, Task<UserInputResponse>> handler)
     {
         _userInputHandler = handler;
     }
@@ -801,7 +843,7 @@ internal void RegisterCommands(IEnumerable<CommandDefinition>? commands)
     /// Registers an elicitation handler for this session.
     /// </summary>
     /// <param name="handler">The handler to invoke when an elicitation request is received.</param>
-    internal void RegisterElicitationHandler(ElicitationHandler? handler)
+    internal void RegisterElicitationHandler(Func<ElicitationContext, Task<ElicitationResult>>? handler)
     {
         _elicitationHandler = handler;
     }
@@ -810,7 +852,7 @@ internal void RegisterElicitationHandler(ElicitationHandler? handler)
     /// Registers an exit-plan-mode handler for this session.
     /// </summary>
     /// <param name="handler">The handler to invoke when an exit-plan-mode request is received.</param>
-    internal void RegisterExitPlanModeHandler(ExitPlanModeHandler? handler)
+    internal void RegisterExitPlanModeHandler(Func<ExitPlanModeRequest, ExitPlanModeInvocation, Task<ExitPlanModeResult>>? handler)
     {
         _exitPlanModeHandler = handler;
     }
@@ -819,7 +861,7 @@ internal void RegisterExitPlanModeHandler(ExitPlanModeHandler? handler)
     /// Registers an auto-mode-switch handler for this session.
     /// </summary>
     /// <param name="handler">The handler to invoke when an auto-mode-switch request is received.</param>
-    internal void RegisterAutoModeSwitchHandler(AutoModeSwitchHandler? handler)
+    internal void RegisterAutoModeSwitchHandler(Func<AutoModeSwitchRequest, AutoModeSwitchInvocation, Task<AutoModeSwitchResponse>>? handler)
     {
         _autoModeSwitchHandler = handler;
     }
@@ -958,7 +1000,7 @@ private void AssertElicitation()
     /// </summary>
     private sealed class SessionUiApiImpl(CopilotSession session) : ISessionUiApi
     {
-        public async Task<ElicitationResult> ElicitationAsync(ElicitationParams elicitationParams, CancellationToken cancellationToken)
+        public async Task<ElicitationResult> ElicitAsync(ElicitationParams elicitationParams, CancellationToken cancellationToken)
         {
             ArgumentNullException.ThrowIfNull(elicitationParams);
             session.ThrowIfDisposed();
@@ -1041,7 +1083,7 @@ public async Task<bool> ConfirmAsync(string message, CancellationToken cancellat
             return null;
         }
 
-        public async Task<string?> InputAsync(string message, InputOptions? options, CancellationToken cancellationToken)
+        public async Task<string?> InputAsync(string message, UiInputOptions? options, CancellationToken cancellationToken)
         {
             ArgumentNullException.ThrowIfNull(message);
             session.ThrowIfDisposed();
@@ -1319,7 +1361,7 @@ internal async Task<SystemMessageTransformRpcResponse> HandleSystemMessageTransf
     /// </remarks>
     /// <example>
     /// <code>
-    /// var events = await session.GetMessagesAsync();
+    /// var events = await session.GetEventsAsync();
     /// foreach (var evt in events)
     /// {
     ///     if (evt is AssistantMessageEvent)
@@ -1329,7 +1371,7 @@ internal async Task<SystemMessageTransformRpcResponse> HandleSystemMessageTransf
     /// }
     /// </code>
     /// </example>
-    public async Task<IReadOnlyList<SessionEvent>> GetMessagesAsync(CancellationToken cancellationToken = default)
+    public async Task<IReadOnlyList<SessionEvent>> GetEventsAsync(CancellationToken cancellationToken = default)
     {
         ThrowIfDisposed();
 
@@ -1437,7 +1479,7 @@ public async Task LogAsync(string message, SessionLogLevel? level = null, bool?
     /// <returns>A task representing the dispose operation.</returns>
     /// <remarks>
     /// <para>
-    /// The caller should ensure the session is idle (e.g., <see cref="SendAndWaitAsync"/>
+    /// The caller should ensure the session is idle (e.g., <see cref="SendAndWaitAsync(MessageOptions, TimeSpan?, CancellationToken)"/>
     /// has returned) before disposing. If the session is not idle, in-flight event handlers
     /// or tool handlers may observe failures.
     /// </para>
@@ -1491,7 +1533,7 @@ await InvokeRpcAsync<object>(
             GC.SuppressFinalize(this);
         }
 
-        _eventHandlers = ImmutableInterlocked.InterlockedExchange(ref _eventHandlers, ImmutableArray<SessionEventHandler>.Empty);
+        _eventHandlers = ImmutableInterlocked.InterlockedExchange(ref _eventHandlers, ImmutableArray<EventSubscription>.Empty);
         _toolHandlers.Clear();
         _commandHandlers.Clear();
 
diff --git a/dotnet/src/SessionFsProvider.cs b/dotnet/src/SessionFsProvider.cs
index 3e3638c83..12dfc8770 100644
--- a/dotnet/src/SessionFsProvider.cs
+++ b/dotnet/src/SessionFsProvider.cs
@@ -1,17 +1,17 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
+using GitHub.Copilot.Rpc;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 /// <summary>
 /// Result of a SQLite query execution via <see cref="ISessionFsSqliteProvider"/>.
 /// Same shape as <see cref="SessionFsSqliteQueryResult"/> but without the <c>Error</c> field,
 /// since providers signal errors by throwing.
 /// </summary>
-public class SessionFsSqliteResult
+public sealed class SessionFsSqliteResult
 {
     /// <summary>Column names from the result set.</summary>
     public IList<string> Columns { get; set; } = [];
@@ -99,24 +99,24 @@ public abstract class SessionFsProvider : ISessionFsHandler
     /// <param name="recursive">Whether to create parent directories.</param>
     /// <param name="mode">Optional POSIX-style permission mode (e.g., 0x1FF for 0777). Null means use OS default.</param>
     /// <param name="cancellationToken">Cancellation token.</param>
-    protected abstract Task MkdirAsync(string path, bool recursive, int? mode, CancellationToken cancellationToken);
+    protected abstract Task MakeDirectoryAsync(string path, bool recursive, int? mode, CancellationToken cancellationToken);
 
     /// <summary>Lists entry names in a directory. Throw if the directory does not exist.</summary>
     /// <param name="path">SessionFs-relative path.</param>
     /// <param name="cancellationToken">Cancellation token.</param>
-    protected abstract Task<IList<string>> ReaddirAsync(string path, CancellationToken cancellationToken);
+    protected abstract Task<IList<string>> ReadDirectoryAsync(string path, CancellationToken cancellationToken);
 
     /// <summary>Lists entries with type info in a directory. Throw if the directory does not exist.</summary>
     /// <param name="path">SessionFs-relative path.</param>
     /// <param name="cancellationToken">Cancellation token.</param>
-    protected abstract Task<IList<SessionFsReaddirWithTypesEntry>> ReaddirWithTypesAsync(string path, CancellationToken cancellationToken);
+    protected abstract Task<IList<SessionFsReaddirWithTypesEntry>> ReadDirectoryWithTypesAsync(string path, CancellationToken cancellationToken);
 
     /// <summary>Removes a file or directory. Throw if the path does not exist (unless <paramref name="force"/> is true).</summary>
     /// <param name="path">SessionFs-relative path.</param>
     /// <param name="recursive">Whether to remove directory contents recursively.</param>
     /// <param name="force">If true, do not throw when the path does not exist.</param>
     /// <param name="cancellationToken">Cancellation token.</param>
-    protected abstract Task RmAsync(string path, bool recursive, bool force, CancellationToken cancellationToken);
+    protected abstract Task RemoveAsync(string path, bool recursive, bool force, CancellationToken cancellationToken);
 
     /// <summary>Renames/moves a file or directory.</summary>
     /// <param name="src">Source path.</param>
@@ -206,7 +206,7 @@ async Task<SessionFsStatResult> ISessionFsHandler.StatAsync(SessionFsStatRequest
 
         try
         {
-            await MkdirAsync(request.Path, request.Recursive ?? false, (int?)request.Mode, cancellationToken).ConfigureAwait(false);
+            await MakeDirectoryAsync(request.Path, request.Recursive ?? false, (int?)request.Mode, cancellationToken).ConfigureAwait(false);
             return null;
         }
         catch (Exception ex)
@@ -221,7 +221,7 @@ async Task<SessionFsReaddirResult> ISessionFsHandler.ReaddirAsync(SessionFsReadd
 
         try
         {
-            var entries = await ReaddirAsync(request.Path, cancellationToken).ConfigureAwait(false);
+            var entries = await ReadDirectoryAsync(request.Path, cancellationToken).ConfigureAwait(false);
             return new SessionFsReaddirResult { Entries = entries };
         }
         catch (Exception ex)
@@ -236,7 +236,7 @@ async Task<SessionFsReaddirWithTypesResult> ISessionFsHandler.ReaddirWithTypesAs
 
         try
         {
-            var entries = await ReaddirWithTypesAsync(request.Path, cancellationToken).ConfigureAwait(false);
+            var entries = await ReadDirectoryWithTypesAsync(request.Path, cancellationToken).ConfigureAwait(false);
             return new SessionFsReaddirWithTypesResult { Entries = entries };
         }
         catch (Exception ex)
@@ -251,7 +251,7 @@ async Task<SessionFsReaddirWithTypesResult> ISessionFsHandler.ReaddirWithTypesAs
 
         try
         {
-            await RmAsync(request.Path, request.Recursive ?? false, request.Force ?? false, cancellationToken).ConfigureAwait(false);
+            await RemoveAsync(request.Path, request.Recursive ?? false, request.Force ?? false, cancellationToken).ConfigureAwait(false);
             return null;
         }
         catch (Exception ex)
diff --git a/dotnet/src/Telemetry.cs b/dotnet/src/Telemetry.cs
index 6bae267a9..893992e10 100644
--- a/dotnet/src/Telemetry.cs
+++ b/dotnet/src/Telemetry.cs
@@ -4,7 +4,7 @@
 
 using System.Diagnostics;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 internal static class TelemetryHelpers
 {
diff --git a/dotnet/src/Types.cs b/dotnet/src/Types.cs
index 99e2f142d..9cc070f78 100644
--- a/dotnet/src/Types.cs
+++ b/dotnet/src/Types.cs
@@ -1,8 +1,8 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
+using GitHub.Copilot.Rpc;
 using Microsoft.Extensions.AI;
 using Microsoft.Extensions.Logging;
 using System.ComponentModel;
@@ -11,7 +11,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 
 internal static class GeneratedStringEnumJson
 {
@@ -50,29 +50,166 @@ internal static class Diagnostics
 }
 
 /// <summary>
-/// Represents the connection state of the Copilot client.
+/// Log level for the Copilot runtime. Use the well-known values exposed as
+/// static members (<see cref="None"/>, <see cref="Error"/>, <see cref="Warning"/>,
+/// <see cref="Info"/>, <see cref="Debug"/>, <see cref="All"/>), or construct
+/// your own with <see cref="CopilotLogLevel(string)"/> if the runtime accepts
+/// additional values. The runtime does not necessarily treat the values as a
+/// linear scale, so do not assume <c>&lt;</c>/<c>&gt;</c> comparisons are meaningful.
 /// </summary>
-[JsonConverter(typeof(JsonStringEnumConverter<ConnectionState>))]
-public enum ConnectionState
+[DebuggerDisplay("{Value,nq}")]
+public readonly struct CopilotLogLevel : IEquatable<CopilotLogLevel>
+{
+    /// <summary>Disable logging entirely.</summary>
+    public static CopilotLogLevel None { get; } = new("none");
+
+    /// <summary>Log only errors.</summary>
+    public static CopilotLogLevel Error { get; } = new("error");
+
+    /// <summary>Log warnings and errors.</summary>
+    public static CopilotLogLevel Warning { get; } = new("warning");
+
+    /// <summary>Log informational messages, warnings, and errors.</summary>
+    public static CopilotLogLevel Info { get; } = new("info");
+
+    /// <summary>Log debug-level diagnostics in addition to the above.</summary>
+    public static CopilotLogLevel Debug { get; } = new("debug");
+
+    /// <summary>Log every diagnostic the runtime emits.</summary>
+    public static CopilotLogLevel All { get; } = new("all");
+
+    /// <summary>Gets the underlying string value of this <see cref="CopilotLogLevel"/>.</summary>
+    public string Value => _value ?? string.Empty;
+
+    private readonly string? _value;
+
+    /// <summary>Initializes a new instance of the <see cref="CopilotLogLevel"/> struct.</summary>
+    /// <param name="value">The wire string value for this log level.</param>
+    public CopilotLogLevel(string value) => _value = value;
+
+    /// <inheritdoc/>
+    public static bool operator ==(CopilotLogLevel left, CopilotLogLevel right) => left.Equals(right);
+
+    /// <inheritdoc/>
+    public static bool operator !=(CopilotLogLevel left, CopilotLogLevel right) => !left.Equals(right);
+
+    /// <inheritdoc/>
+    public override bool Equals([NotNullWhen(true)] object? obj) => obj is CopilotLogLevel other && Equals(other);
+
+    /// <inheritdoc/>
+    public bool Equals(CopilotLogLevel other) => string.Equals(Value, other.Value, StringComparison.OrdinalIgnoreCase);
+
+    /// <inheritdoc/>
+    public override int GetHashCode() => StringComparer.OrdinalIgnoreCase.GetHashCode(Value);
+
+    /// <inheritdoc/>
+    public override string ToString() => Value;
+}
+
+/// <summary>
+/// Configures how a <see cref="CopilotClient"/> connects to the Copilot runtime.
+/// Use the factory methods on this class to construct an instance.
+/// </summary>
+public abstract class RuntimeConnection
+{
+    internal RuntimeConnection() { }
+
+    /// <summary>
+    /// Spawn a runtime child process and communicate over its stdin/stdout.
+    /// This is the default if no <see cref="CopilotClientOptions.Connection"/> is set.
+    /// </summary>
+    /// <param name="path">Path to the runtime executable. When <c>null</c>, the bundled runtime is used.</param>
+    /// <param name="args">Extra command-line arguments to pass to the runtime process.</param>
+    public static StdioRuntimeConnection ForStdio(string? path = null, IList<string>? args = null)
+        => new() { Path = path, Args = args };
+
+    /// <summary>
+    /// Spawn a runtime child process that listens on a TCP socket and connect to it.
+    /// </summary>
+    /// <param name="port">TCP port to listen on. <c>0</c> (the default) auto-allocates a free port.
+    /// If the chosen port is already in use, startup fails.</param>
+    /// <param name="connectionToken">Optional shared secret the SDK sends to the spawned runtime to authenticate the TCP connection.
+    /// When <c>null</c>, a GUID is generated automatically.</param>
+    /// <param name="path">Path to the runtime executable. When <c>null</c>, the bundled runtime is used.</param>
+    /// <param name="args">Extra command-line arguments to pass to the runtime process.</param>
+    public static TcpRuntimeConnection ForTcp(int port = 0, string? connectionToken = null, string? path = null, IList<string>? args = null)
+        => new() { Port = port, ConnectionToken = connectionToken, Path = path, Args = args };
+
+    /// <summary>
+    /// Connect to an already-running runtime at a given URI.
+    /// </summary>
+    /// <param name="url">URL of the runtime to connect to. Accepts <c>"port"</c>, <c>"host:port"</c>, or a full URL.</param>
+    /// <param name="connectionToken">Optional shared secret to authenticate the connection.</param>
+    public static UriRuntimeConnection ForUri(string url, string? connectionToken = null)
+        => new() { Url = url, ConnectionToken = connectionToken };
+}
+
+/// <summary>
+/// Base for <see cref="RuntimeConnection"/> kinds that spawn a runtime child process.
+/// </summary>
+public abstract class ChildProcessRuntimeConnection : RuntimeConnection
+{
+    internal ChildProcessRuntimeConnection() { }
+
+    /// <summary>Path to the runtime executable. When <c>null</c>, the bundled runtime is used.</summary>
+    public string? Path { get; set; }
+
+    /// <summary>Extra command-line arguments to pass to the runtime process.</summary>
+    public IList<string>? Args { get; set; }
+}
+
+/// <summary>
+/// Spawns a runtime child process and communicates over stdin/stdout. Construct via
+/// <see cref="RuntimeConnection.ForStdio(string?, IList{string}?)"/>.
+/// </summary>
+public sealed class StdioRuntimeConnection : ChildProcessRuntimeConnection
+{
+    internal StdioRuntimeConnection() { }
+}
+
+/// <summary>
+/// Spawns a runtime child process listening on a TCP socket. Construct via
+/// <see cref="RuntimeConnection.ForTcp(int, string?, string?, IList{string}?)"/>.
+/// </summary>
+public sealed class TcpRuntimeConnection : ChildProcessRuntimeConnection
+{
+    internal TcpRuntimeConnection() { }
+
+    /// <summary>
+    /// TCP port to listen on. <c>0</c> (the default) auto-allocates a free port.
+    /// If the chosen port is already in use, startup fails.
+    /// </summary>
+    public int Port { get; set; }
+
+    /// <summary>
+    /// Optional shared secret the SDK sends to the spawned runtime to authenticate
+    /// the TCP connection. When <c>null</c>, a GUID is generated automatically.
+    /// </summary>
+    public string? ConnectionToken { get; set; }
+}
+
+/// <summary>
+/// Connects to an already-running runtime at the specified URL. Construct via
+/// <see cref="RuntimeConnection.ForUri(string, string?)"/>.
+/// </summary>
+public sealed class UriRuntimeConnection : RuntimeConnection
 {
-    /// <summary>The client is not connected to the server.</summary>
-    [JsonStringEnumMemberName("disconnected")]
-    Disconnected,
-    /// <summary>The client is establishing a connection to the server.</summary>
-    [JsonStringEnumMemberName("connecting")]
-    Connecting,
-    /// <summary>The client is connected and ready to communicate.</summary>
-    [JsonStringEnumMemberName("connected")]
-    Connected,
-    /// <summary>The connection is in an error state.</summary>
-    [JsonStringEnumMemberName("error")]
-    Error
+    internal UriRuntimeConnection() { }
+
+    /// <summary>
+    /// URL of the runtime to connect to. Accepts <c>"port"</c>, <c>"host:port"</c>,
+    /// or a full URL.
+    /// </summary>
+    public required string Url { get; set; }
+
+    /// <summary>Optional shared secret to authenticate the connection.</summary>
+    public string? ConnectionToken { get; set; }
 }
 
 /// <summary>
 /// Configuration options for creating a <see cref="CopilotClient"/> instance.
 /// </summary>
-public class CopilotClientOptions
+public sealed class CopilotClientOptions
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="CopilotClientOptions"/> class.
@@ -83,113 +220,71 @@ public CopilotClientOptions() { }
     /// Initializes a new instance of the <see cref="CopilotClientOptions"/> class
     /// by copying the properties of the specified instance.
     /// </summary>
-    protected CopilotClientOptions(CopilotClientOptions? other)
+    private CopilotClientOptions(CopilotClientOptions? other)
     {
         if (other is null) return;
 
-        AutoStart = other.AutoStart;
-#pragma warning disable CS0618 // Obsolete member
-        AutoRestart = other.AutoRestart;
-#pragma warning restore CS0618
-        CliArgs = (string[]?)other.CliArgs?.Clone();
-        CliPath = other.CliPath;
-        CliUrl = other.CliUrl;
-        Cwd = other.Cwd;
-        CopilotHome = other.CopilotHome;
+        Connection = other.Connection;
+        WorkingDirectory = other.WorkingDirectory;
+        BaseDirectory = other.BaseDirectory;
         Environment = other.Environment;
         GitHubToken = other.GitHubToken;
         Logger = other.Logger;
         LogLevel = other.LogLevel;
-        Port = other.Port;
         Telemetry = other.Telemetry;
         UseLoggedInUser = other.UseLoggedInUser;
-        UseStdio = other.UseStdio;
         OnListModels = other.OnListModels;
         SessionFs = other.SessionFs;
         SessionIdleTimeoutSeconds = other.SessionIdleTimeoutSeconds;
-        TcpConnectionToken = other.TcpConnectionToken;
-        Remote = other.Remote;
+        EnableRemoteSessions = other.EnableRemoteSessions;
     }
 
     /// <summary>
-    /// Path to the Copilot CLI executable. If not specified, uses the bundled CLI from the SDK.
-    /// </summary>
-    public string? CliPath { get; set; }
-    /// <summary>
-    /// Additional command-line arguments to pass to the CLI process.
+    /// How to connect to the runtime. When <c>null</c>, the default is
+    /// <see cref="RuntimeConnection.ForStdio(string?, IList{string}?)"/> with the bundled runtime.
     /// </summary>
-    public string[]? CliArgs { get; set; }
+    public RuntimeConnection? Connection { get; set; }
+
     /// <summary>
-    /// Working directory for the CLI process.
+    /// Working directory for the runtime process.
     /// </summary>
-    public string? Cwd { get; set; }
+    public string? WorkingDirectory { get; set; }
+
     /// <summary>
     /// Base directory for Copilot data (session state, config, etc.).
-    /// Sets the <c>COPILOT_HOME</c> environment variable on the spawned CLI process.
-    /// When <see langword="null"/>, the CLI defaults to <c>~/.copilot</c>.
-    /// This option is only used when the SDK spawns the CLI process; it is ignored
-    /// when connecting to an external server via <see cref="CliUrl"/>.
-    /// </summary>
-    public string? CopilotHome { get; set; }
-    /// <summary>
-    /// Port number for the CLI server when not using stdio transport.
-    /// </summary>
-    public int Port { get; set; }
-    /// <summary>
-    /// Whether to use stdio transport for communication with the CLI server.
-    /// Defaults to <c>true</c> when neither <see cref="CliUrl"/> nor <see cref="Port"/>
-    /// switches the client into TCP mode. Setting this to <c>true</c> is mutually
-    /// exclusive with <see cref="CliUrl"/>.
-    /// </summary>
-    public bool? UseStdio { get; set; }
-    /// <summary>
-    /// URL of an existing CLI server to connect to instead of starting a new one.
-    /// </summary>
-    public string? CliUrl { get; set; }
-    /// <summary>
-    /// Log level for the CLI server (e.g., "info", "debug", "warn", "error").
+    /// Sets the <c>COPILOT_HOME</c> environment variable on the spawned runtime.
+    /// When <see langword="null"/>, the runtime defaults to <c>~/.copilot</c>.
+    /// Ignored when connecting to an existing runtime via
+    /// <see cref="RuntimeConnection.ForUri(string, string?)"/>.
     /// </summary>
-    public string LogLevel { get; set; } = "info";
-    /// <summary>
-    /// Whether to automatically start the CLI server if it is not already running.
-    /// </summary>
-    public bool AutoStart { get; set; } = true;
-    /// <summary>
-    /// Obsolete. This option has no effect.
-    /// </summary>
-    [EditorBrowsable(EditorBrowsableState.Never)]
-    [Obsolete("AutoRestart has no effect and will be removed in a future release.")]
-    public bool AutoRestart { get; set; }
+    public string? BaseDirectory { get; set; }
+
     /// <summary>
-    /// Environment variables to pass to the CLI process.
+    /// Log level for the Copilot runtime. Use the well-known values on
+    /// <see cref="CopilotLogLevel"/> (<see cref="CopilotLogLevel.None"/>,
+    /// <see cref="CopilotLogLevel.Error"/>, <see cref="CopilotLogLevel.Warning"/>,
+    /// <see cref="CopilotLogLevel.Info"/>, <see cref="CopilotLogLevel.Debug"/>,
+    /// <see cref="CopilotLogLevel.All"/>). When <c>null</c>, the runtime's default
+    /// log level is used.
     /// </summary>
+    public CopilotLogLevel? LogLevel { get; set; }
+
+    /// <summary>Environment variables to pass to the runtime process.</summary>
     public IReadOnlyDictionary<string, string>? Environment { get; set; }
-    /// <summary>
-    /// Logger instance for SDK diagnostic output.
-    /// </summary>
+
+    /// <summary>Logger instance for SDK diagnostic output.</summary>
     public ILogger? Logger { get; set; }
 
     /// <summary>
     /// GitHub token to use for authentication.
-    /// When provided, the token is passed to the CLI server via environment variable.
+    /// When provided, the token is passed to the runtime via environment variable.
     /// This takes priority over other authentication methods.
     /// </summary>
     public string? GitHubToken { get; set; }
 
-    /// <summary>
-    /// Obsolete. Use <see cref="GitHubToken"/> instead.
-    /// </summary>
-    [EditorBrowsable(EditorBrowsableState.Never)]
-    [Obsolete("Use GitHubToken instead.", error: false)]
-    public string? GithubToken
-    {
-        get => GitHubToken;
-        set => GitHubToken = value;
-    }
-
     /// <summary>
     /// Whether to use the logged-in user for authentication.
-    /// When true, the CLI server will attempt to use stored OAuth tokens or gh CLI auth.
+    /// When true, the runtime will attempt to use stored OAuth tokens or gh CLI auth.
     /// When false, only explicit tokens (GitHubToken or environment variables) are used.
     /// Default: true (but defaults to false when GitHubToken is provided).
     /// </summary>
@@ -198,7 +293,7 @@ public string? GithubToken
     /// <summary>
     /// Custom handler for listing available models.
     /// When provided, <c>ListModelsAsync()</c> calls this handler instead of
-    /// querying the CLI server. Useful in BYOK mode to return models
+    /// querying the runtime. Useful in BYOK mode to return models
     /// available from your custom provider.
     /// </summary>
     public Func<CancellationToken, Task<IList<ModelInfo>>>? OnListModels { get; set; }
@@ -207,13 +302,13 @@ public string? GithubToken
     /// Custom session filesystem provider configuration.
     /// When set, the client registers as the session filesystem provider on connect,
     /// routing session-scoped file I/O through per-session handlers created via
-    /// <see cref="SessionConfig.CreateSessionFsHandler"/> or <see cref="ResumeSessionConfig.CreateSessionFsHandler"/>.
+    /// <see cref="SessionConfigBase.CreateSessionFsProvider"/>.
     /// </summary>
     public SessionFsConfig? SessionFs { get; set; }
 
     /// <summary>
-    /// OpenTelemetry configuration for the CLI server.
-    /// When set to a non-<see langword="null"/> instance, the CLI server is started with OpenTelemetry instrumentation enabled.
+    /// OpenTelemetry configuration for the runtime.
+    /// When set to a non-<see langword="null"/> instance, the runtime is started with OpenTelemetry instrumentation enabled.
     /// </summary>
     public TelemetryConfig? Telemetry { get; set; }
 
@@ -221,26 +316,19 @@ public string? GithubToken
     /// Server-wide idle timeout for sessions in seconds.
     /// Sessions without activity for this duration are automatically cleaned up.
     /// Set to <c>0</c> or leave as <see langword="null"/> to disable (sessions live indefinitely).
-    /// This option is only used when the SDK spawns the CLI process; it is ignored
-    /// when connecting to an external server via <see cref="CliUrl"/>.
+    /// This option is only used when the SDK spawns the runtime; it is ignored
+    /// when connecting to an external runtime via <see cref="RuntimeConnection.ForUri(string, string?)"/>.
     /// </summary>
     public int? SessionIdleTimeoutSeconds { get; set; }
 
-    /// <summary>
-    /// Connection token for the headless CLI server (TCP only). When the SDK spawns its own
-    /// CLI in TCP mode and this is omitted, a GUID is generated automatically so the loopback
-    /// listener is safe by default. Cannot be combined with <see cref="UseStdio"/> = true.
-    /// </summary>
-    public string? TcpConnectionToken { get; set; }
-
     /// <summary>
     /// Enable remote session support (Mission Control integration).
     /// When true, sessions in a GitHub repository working directory are
     /// accessible from GitHub web and mobile.
-    /// This option is only used when the SDK spawns the CLI process; it is ignored
-    /// when connecting to an external server via <see cref="CliUrl"/>.
+    /// This option is only used when the SDK spawns the runtime; it is ignored
+    /// when connecting to an external runtime via <see cref="RuntimeConnection.ForUri(string, string?)"/>.
     /// </summary>
-    public bool Remote { get; set; }
+    public bool EnableRemoteSessions { get; set; }
 
     /// <summary>
     /// Creates a shallow clone of this <see cref="CopilotClientOptions"/> instance.
@@ -251,10 +339,7 @@ public string? GithubToken
     /// Other reference-type properties (for example delegates and the logger) are not
     /// deep-cloned; the original and the clone will share those objects.
     /// </remarks>
-    public virtual CopilotClientOptions Clone()
-    {
-        return new(this);
-    }
+    public CopilotClientOptions Clone() => new(this);
 }
 
 /// <summary>
@@ -335,7 +420,7 @@ public sealed class SessionFsConfig
 /// <summary>
 /// Represents a binary result returned by a tool invocation.
 /// </summary>
-public class ToolBinaryResult
+public sealed class ToolBinaryResult
 {
     /// <summary>
     /// Base64-encoded binary data.
@@ -350,10 +435,11 @@ public class ToolBinaryResult
     public string MimeType { get; set; } = string.Empty;
 
     /// <summary>
-    /// Type identifier for the binary result.
+    /// Type identifier for the binary result. Use the well-known values on
+    /// <see cref="ToolBinaryResultType"/> (<c>"image"</c>, <c>"resource"</c>).
     /// </summary>
     [JsonPropertyName("type")]
-    public string Type { get; set; } = string.Empty;
+    public ToolBinaryResultType Type { get; set; }
 
     /// <summary>
     /// Optional human-readable description of the binary result.
@@ -362,10 +448,76 @@ public class ToolBinaryResult
     public string? Description { get; set; }
 }
 
+/// <summary>Describes the kind of a <see cref="ToolBinaryResult"/>.</summary>
+[JsonConverter(typeof(ToolBinaryResultType.Converter))]
+[DebuggerDisplay("{Value,nq}")]
+public readonly struct ToolBinaryResultType : IEquatable<ToolBinaryResultType>
+{
+    /// <summary>Gets the kind indicating an inline image result.</summary>
+    public static ToolBinaryResultType Image { get; } = new("image");
+
+    /// <summary>Gets the kind indicating an MCP resource result.</summary>
+    public static ToolBinaryResultType Resource { get; } = new("resource");
+
+    /// <summary>Gets the underlying string value of this <see cref="ToolBinaryResultType"/>.</summary>
+    public string Value => _value ?? string.Empty;
+
+    private readonly string? _value;
+
+    /// <summary>Initializes a new instance of the <see cref="ToolBinaryResultType"/> struct.</summary>
+    /// <param name="value">The string value for this type.</param>
+    [JsonConstructor]
+    public ToolBinaryResultType(string value) => _value = value;
+
+    /// <inheritdoc/>
+    public static bool operator ==(ToolBinaryResultType left, ToolBinaryResultType right) => left.Equals(right);
+
+    /// <inheritdoc/>
+    public static bool operator !=(ToolBinaryResultType left, ToolBinaryResultType right) => !left.Equals(right);
+
+    /// <inheritdoc/>
+    public override bool Equals([NotNullWhen(true)] object? obj) => obj is ToolBinaryResultType other && Equals(other);
+
+    /// <inheritdoc/>
+    public bool Equals(ToolBinaryResultType other) => string.Equals(Value, other.Value, StringComparison.OrdinalIgnoreCase);
+
+    /// <inheritdoc/>
+    public override int GetHashCode() => StringComparer.OrdinalIgnoreCase.GetHashCode(Value);
+
+    /// <inheritdoc/>
+    public override string ToString() => Value;
+
+    /// <summary>Provides a <see cref="JsonConverter{ToolBinaryResultType}"/> for serializing <see cref="ToolBinaryResultType"/> instances.</summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public sealed class Converter : JsonConverter<ToolBinaryResultType>
+    {
+        /// <inheritdoc/>
+        public override ToolBinaryResultType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            if (reader.TokenType != JsonTokenType.String)
+            {
+                throw new JsonException("Expected string for ToolBinaryResultType.");
+            }
+
+            var value = reader.GetString();
+            if (value is null)
+            {
+                throw new JsonException("ToolBinaryResultType value cannot be null.");
+            }
+
+            return new ToolBinaryResultType(value);
+        }
+
+        /// <inheritdoc/>
+        public override void Write(Utf8JsonWriter writer, ToolBinaryResultType value, JsonSerializerOptions options) =>
+            writer.WriteStringValue(value.Value);
+    }
+}
+
 /// <summary>
 /// Represents the structured result of a tool execution.
 /// </summary>
-public class ToolResultObject
+public sealed class ToolResultObject
 {
     /// <summary>
     /// Text result to be consumed by the language model.
@@ -477,7 +629,7 @@ private static ToolResultObject ConvertAIContents(IEnumerable<AIContent> content
                     {
                         Data = dataContent.Base64Data.ToString(),
                         MimeType = dataContent.MediaType ?? "application/octet-stream",
-                        Type = dataContent.HasTopLevelMediaType("image") ? "image" : "resource",
+                        Type = dataContent.HasTopLevelMediaType("image") ? ToolBinaryResultType.Image : ToolBinaryResultType.Resource,
                     });
                     break;
 
@@ -502,7 +654,7 @@ private static string SerializeAIContent(AIContent content) =>
 /// <summary>
 /// Contains context for a tool invocation callback.
 /// </summary>
-public class ToolInvocation
+public sealed class ToolInvocation
 {
     /// <summary>
     /// Identifier of the session that triggered the tool call.
@@ -522,11 +674,6 @@ public class ToolInvocation
     public object? Arguments { get; set; }
 }
 
-/// <summary>
-/// Delegate for handling tool invocations and returning a result.
-/// </summary>
-public delegate Task<object?> ToolHandler(ToolInvocation invocation);
-
 /// <summary>Describes the kind of a permission request result.</summary>
 [JsonConverter(typeof(PermissionRequestResultKind.Converter))]
 [DebuggerDisplay("{Value,nq}")]
@@ -544,21 +691,6 @@ public class ToolInvocation
     /// <summary>Gets the kind indicating no permission decision was made.</summary>
     public static PermissionRequestResultKind NoResult { get; } = new("no-result");
 
-    /// <summary>Deprecated. Use <see cref="Rejected"/> instead.</summary>
-    [EditorBrowsable(EditorBrowsableState.Never)]
-    [Obsolete("Use Rejected instead.")]
-    public static PermissionRequestResultKind DeniedInteractivelyByUser => Rejected;
-
-    /// <summary>Deprecated. Use <see cref="UserNotAvailable"/> instead.</summary>
-    [EditorBrowsable(EditorBrowsableState.Never)]
-    [Obsolete("Use UserNotAvailable instead.")]
-    public static PermissionRequestResultKind DeniedCouldNotRequestFromUser => UserNotAvailable;
-
-    /// <summary>Deprecated. Use <see cref="UserNotAvailable"/> instead.</summary>
-    [EditorBrowsable(EditorBrowsableState.Never)]
-    [Obsolete("Use UserNotAvailable instead.")]
-    public static PermissionRequestResultKind DeniedByRules => UserNotAvailable;
-
     /// <summary>Gets the underlying string value of this <see cref="PermissionRequestResultKind"/>.</summary>
     public string Value => _value ?? string.Empty;
 
@@ -617,16 +749,16 @@ public override void Write(Utf8JsonWriter writer, PermissionRequestResultKind va
 /// <summary>
 /// Result of a permission request evaluation.
 /// </summary>
-public class PermissionRequestResult
+public sealed class PermissionRequestResult
 {
     /// <summary>
-    /// Permission decision kind. Use the static members of <see cref="PermissionRequestResultKind"/>
-    /// to construct values. Valid kinds are:
+    /// Permission decision kind. Construct values with the static members on
+    /// <see cref="PermissionRequestResultKind"/>:
     /// <list type="bullet">
-    /// <item><description><c>"approve-once"</c> (<see cref="PermissionRequestResultKind.Approved"/>) — allow this single request.</description></item>
-    /// <item><description><c>"reject"</c> (<see cref="PermissionRequestResultKind.Rejected"/>) — deny the request.</description></item>
-    /// <item><description><c>"user-not-available"</c> (<see cref="PermissionRequestResultKind.UserNotAvailable"/>) — deny because no user is available to confirm.</description></item>
-    /// <item><description><c>"no-result"</c> (<see cref="PermissionRequestResultKind.NoResult"/>) — leave the pending request unanswered (protocol v1 only; rejected by protocol v2 servers).</description></item>
+    /// <item><description><see cref="PermissionRequestResultKind.Approved"/> — allow this single request.</description></item>
+    /// <item><description><see cref="PermissionRequestResultKind.Rejected"/> — deny the request.</description></item>
+    /// <item><description><see cref="PermissionRequestResultKind.UserNotAvailable"/> — deny because no user is available to confirm.</description></item>
+    /// <item><description><see cref="PermissionRequestResultKind.NoResult"/> — leave the pending request unanswered (protocol v1 only; rejected by protocol v2 servers).</description></item>
     /// </list>
     /// </summary>
     [JsonPropertyName("kind")]
@@ -637,12 +769,20 @@ public class PermissionRequestResult
     /// </summary>
     [JsonPropertyName("rules")]
     public IList<object>? Rules { get; set; }
+
+    /// <summary>
+    /// Optional human-readable feedback to forward to the LLM along with the
+    /// decision. Mirrors the <c>feedback</c> field on the RPC-level
+    /// <see cref="Rpc.PermissionDecision"/> type.
+    /// </summary>
+    [JsonPropertyName("feedback")]
+    public string? Feedback { get; set; }
 }
 
 /// <summary>
 /// Contains context for a permission request callback.
 /// </summary>
-public class PermissionInvocation
+public sealed class PermissionInvocation
 {
     /// <summary>
     /// Identifier of the session that triggered the permission request.
@@ -650,11 +790,6 @@ public class PermissionInvocation
     public string SessionId { get; set; } = string.Empty;
 }
 
-/// <summary>
-/// Delegate for handling permission requests and returning a decision.
-/// </summary>
-public delegate Task<PermissionRequestResult> PermissionRequestHandler(PermissionRequest request, PermissionInvocation invocation);
-
 // ============================================================================
 // User Input Handler Types
 // ============================================================================
@@ -662,7 +797,7 @@ public class PermissionInvocation
 /// <summary>
 /// Request for user input from the agent.
 /// </summary>
-public class UserInputRequest
+public sealed class UserInputRequest
 {
     /// <summary>
     /// The question to ask the user.
@@ -686,7 +821,7 @@ public class UserInputRequest
 /// <summary>
 /// Response to a user input request.
 /// </summary>
-public class UserInputResponse
+public sealed class UserInputResponse
 {
     /// <summary>
     /// The user's answer.
@@ -704,7 +839,7 @@ public class UserInputResponse
 /// <summary>
 /// Context for a user input request invocation.
 /// </summary>
-public class UserInputInvocation
+public sealed class UserInputInvocation
 {
     /// <summary>
     /// Identifier of the session that triggered the user input request.
@@ -712,15 +847,10 @@ public class UserInputInvocation
     public string SessionId { get; set; } = string.Empty;
 }
 
-/// <summary>
-/// Handler for user input requests from the agent.
-/// </summary>
-public delegate Task<UserInputResponse> UserInputHandler(UserInputRequest request, UserInputInvocation invocation);
-
 /// <summary>
 /// Request to exit plan mode and continue with a selected action.
 /// </summary>
-public class ExitPlanModeRequest
+public sealed class ExitPlanModeRequest
 {
     /// <summary>
     /// Summary of the plan or proposed next step.
@@ -750,7 +880,7 @@ public class ExitPlanModeRequest
 /// <summary>
 /// Response to an exit-plan-mode request.
 /// </summary>
-public class ExitPlanModeResult
+public sealed class ExitPlanModeResult
 {
     /// <summary>
     /// Whether the user approved exiting plan mode.
@@ -774,7 +904,7 @@ public class ExitPlanModeResult
 /// <summary>
 /// Context for an exit-plan-mode request invocation.
 /// </summary>
-public class ExitPlanModeInvocation
+public sealed class ExitPlanModeInvocation
 {
     /// <summary>
     /// Identifier of the session that triggered the request.
@@ -782,15 +912,10 @@ public class ExitPlanModeInvocation
     public string SessionId { get; set; } = string.Empty;
 }
 
-/// <summary>
-/// Handler for exit-plan-mode requests from the agent.
-/// </summary>
-public delegate Task<ExitPlanModeResult> ExitPlanModeHandler(ExitPlanModeRequest request, ExitPlanModeInvocation invocation);
-
 /// <summary>
 /// Request to switch to auto mode after an eligible rate limit.
 /// </summary>
-public class AutoModeSwitchRequest
+public sealed class AutoModeSwitchRequest
 {
     /// <summary>
     /// The rate-limit error code that triggered the request.
@@ -808,7 +933,7 @@ public class AutoModeSwitchRequest
 /// <summary>
 /// Context for an auto-mode-switch request invocation.
 /// </summary>
-public class AutoModeSwitchInvocation
+public sealed class AutoModeSwitchInvocation
 {
     /// <summary>
     /// Identifier of the session that triggered the request.
@@ -816,11 +941,6 @@ public class AutoModeSwitchInvocation
     public string SessionId { get; set; } = string.Empty;
 }
 
-/// <summary>
-/// Handler for auto-mode-switch requests from the agent.
-/// </summary>
-public delegate Task<AutoModeSwitchResponse> AutoModeSwitchHandler(AutoModeSwitchRequest request, AutoModeSwitchInvocation invocation);
-
 // ============================================================================
 // Command Handler Types
 // ============================================================================
@@ -828,7 +948,7 @@ public class AutoModeSwitchInvocation
 /// <summary>
 /// Defines a slash-command that users can invoke from the CLI TUI.
 /// </summary>
-public class CommandDefinition
+public sealed class CommandDefinition
 {
     /// <summary>
     /// Command name (without leading <c>/</c>). For example, <c>"deploy"</c>.
@@ -843,13 +963,13 @@ public class CommandDefinition
     /// <summary>
     /// Handler invoked when the command is executed.
     /// </summary>
-    public required CommandHandler Handler { get; set; }
+    public required Func<CommandContext, Task> Handler { get; set; }
 }
 
 /// <summary>
-/// Context passed to a <see cref="CommandHandler"/> when a command is executed.
+/// Context passed to a command handler when a command is executed.
 /// </summary>
-public class CommandContext
+public sealed class CommandContext
 {
     /// <summary>
     /// Session ID where the command was invoked.
@@ -872,11 +992,6 @@ public class CommandContext
     public string Args { get; set; } = string.Empty;
 }
 
-/// <summary>
-/// Delegate for handling slash-command executions.
-/// </summary>
-public delegate Task CommandHandler(CommandContext context);
-
 // ============================================================================
 // Elicitation Types (UI — client → server)
 // ============================================================================
@@ -884,7 +999,7 @@ public class CommandContext
 /// <summary>
 /// JSON Schema describing the form fields to present for an elicitation dialog.
 /// </summary>
-public class ElicitationSchema
+public sealed class ElicitationSchema
 {
     /// <summary>
     /// Schema type indicator (always <c>"object"</c>).
@@ -908,7 +1023,7 @@ public class ElicitationSchema
 /// <summary>
 /// Parameters for an elicitation request sent from the SDK to the server.
 /// </summary>
-public class ElicitationParams
+public sealed class ElicitationParams
 {
     /// <summary>
     /// Message describing what information is needed from the user.
@@ -924,7 +1039,7 @@ public class ElicitationParams
 /// <summary>
 /// Result returned from an elicitation dialog.
 /// </summary>
-public class ElicitationResult
+public sealed class ElicitationResult
 {
     /// <summary>
     /// User action: <c>"accept"</c> (submitted), <c>"decline"</c> (rejected), or <c>"cancel"</c> (dismissed).
@@ -940,7 +1055,7 @@ public class ElicitationResult
 /// <summary>
 /// Options for the <see cref="ISessionUiApi.InputAsync"/> convenience method.
 /// </summary>
-public class InputOptions
+public sealed class UiInputOptions
 {
     /// <summary>Title label for the input field.</summary>
     public string? Title { get; set; }
@@ -973,7 +1088,7 @@ public interface ISessionUiApi
     /// <param name="cancellationToken">Optional cancellation token.</param>
     /// <returns>The <see cref="ElicitationResult"/> with the user's response.</returns>
     /// <exception cref="InvalidOperationException">Thrown if the host does not support elicitation.</exception>
-    Task<ElicitationResult> ElicitationAsync(ElicitationParams elicitationParams, CancellationToken cancellationToken = default);
+    Task<ElicitationResult> ElicitAsync(ElicitationParams elicitationParams, CancellationToken cancellationToken = default);
 
     /// <summary>
     /// Shows a confirmation dialog and returns the user's boolean answer.
@@ -1005,7 +1120,7 @@ public interface ISessionUiApi
     /// <param name="cancellationToken">Optional cancellation token.</param>
     /// <returns>The entered string, or <c>null</c> if the user declined/cancelled.</returns>
     /// <exception cref="InvalidOperationException">Thrown if the host does not support elicitation.</exception>
-    Task<string?> InputAsync(string message, InputOptions? options = null, CancellationToken cancellationToken = default);
+    Task<string?> InputAsync(string message, UiInputOptions? options = null, CancellationToken cancellationToken = default);
 }
 
 // ============================================================================
@@ -1016,7 +1131,7 @@ public interface ISessionUiApi
 /// Context for an elicitation handler invocation, combining the request data
 /// with session context. Mirrors the single-argument pattern of <see cref="CommandContext"/>.
 /// </summary>
-public class ElicitationContext
+public sealed class ElicitationContext
 {
     /// <summary>Identifier of the session that triggered the elicitation request.</summary>
     public string SessionId { get; set; } = string.Empty;
@@ -1037,11 +1152,6 @@ public class ElicitationContext
     public string? Url { get; set; }
 }
 
-/// <summary>
-/// Delegate for handling elicitation requests from the server.
-/// </summary>
-public delegate Task<ElicitationResult> ElicitationHandler(ElicitationContext context);
-
 // ============================================================================
 // Session Capabilities
 // ============================================================================
@@ -1049,7 +1159,7 @@ public class ElicitationContext
 /// <summary>
 /// Represents the capabilities reported by the host for a session.
 /// </summary>
-public class SessionCapabilities
+public sealed class SessionCapabilities
 {
     /// <summary>
     /// UI-related capabilities.
@@ -1060,7 +1170,7 @@ public class SessionCapabilities
 /// <summary>
 /// UI-specific capability flags for a session.
 /// </summary>
-public class SessionUiCapabilities
+public sealed class SessionUiCapabilities
 {
     /// <summary>
     /// Whether the host supports interactive elicitation dialogs.
@@ -1075,7 +1185,7 @@ public class SessionUiCapabilities
 /// <summary>
 /// Context for a hook invocation.
 /// </summary>
-public class HookInvocation
+public sealed class HookInvocation
 {
     /// <summary>
     /// Identifier of the session that triggered the hook.
@@ -1086,7 +1196,7 @@ public class HookInvocation
 /// <summary>
 /// Input for a pre-tool-use hook.
 /// </summary>
-public class PreToolUseHookInput
+public sealed class PreToolUseHookInput
 {
     /// <summary>
     /// The runtime session ID of the session that triggered the hook.
@@ -1098,7 +1208,8 @@ public class PreToolUseHookInput
     /// Unix timestamp in milliseconds when the tool use was initiated.
     /// </summary>
     [JsonPropertyName("timestamp")]
-    public long Timestamp { get; set; }
+    [JsonConverter(typeof(UnixMillisecondsDateTimeOffsetConverter))]
+    public DateTimeOffset Timestamp { get; set; }
 
     /// <summary>
     /// Current working directory of the session.
@@ -1122,7 +1233,7 @@ public class PreToolUseHookInput
 /// <summary>
 /// Output for a pre-tool-use hook.
 /// </summary>
-public class PreToolUseHookOutput
+public sealed class PreToolUseHookOutput
 {
     /// <summary>
     /// Permission decision for the pending tool call.
@@ -1160,15 +1271,10 @@ public class PreToolUseHookOutput
     public bool? SuppressOutput { get; set; }
 }
 
-/// <summary>
-/// Delegate invoked before a tool is executed, allowing modification or denial of the call.
-/// </summary>
-public delegate Task<PreToolUseHookOutput?> PreToolUseHandler(PreToolUseHookInput input, HookInvocation invocation);
-
 /// <summary>
 /// Input for a post-tool-use hook.
 /// </summary>
-public class PostToolUseHookInput
+public sealed class PostToolUseHookInput
 {
     /// <summary>
     /// The runtime session ID of the session that triggered the hook.
@@ -1180,7 +1286,8 @@ public class PostToolUseHookInput
     /// Unix timestamp in milliseconds when the tool execution completed.
     /// </summary>
     [JsonPropertyName("timestamp")]
-    public long Timestamp { get; set; }
+    [JsonConverter(typeof(UnixMillisecondsDateTimeOffsetConverter))]
+    public DateTimeOffset Timestamp { get; set; }
 
     /// <summary>
     /// Current working directory of the session.
@@ -1210,7 +1317,7 @@ public class PostToolUseHookInput
 /// <summary>
 /// Output for a post-tool-use hook.
 /// </summary>
-public class PostToolUseHookOutput
+public sealed class PostToolUseHookOutput
 {
     /// <summary>
     /// Modified result to replace the original tool result.
@@ -1231,15 +1338,10 @@ public class PostToolUseHookOutput
     public bool? SuppressOutput { get; set; }
 }
 
-/// <summary>
-/// Delegate invoked after a tool has been executed, allowing modification of the result.
-/// </summary>
-public delegate Task<PostToolUseHookOutput?> PostToolUseHandler(PostToolUseHookInput input, HookInvocation invocation);
-
 /// <summary>
 /// Input for a user-prompt-submitted hook.
 /// </summary>
-public class UserPromptSubmittedHookInput
+public sealed class UserPromptSubmittedHookInput
 {
     /// <summary>
     /// The runtime session ID of the session that triggered the hook.
@@ -1251,7 +1353,8 @@ public class UserPromptSubmittedHookInput
     /// Unix timestamp in milliseconds when the prompt was submitted.
     /// </summary>
     [JsonPropertyName("timestamp")]
-    public long Timestamp { get; set; }
+    [JsonConverter(typeof(UnixMillisecondsDateTimeOffsetConverter))]
+    public DateTimeOffset Timestamp { get; set; }
 
     /// <summary>
     /// Current working directory of the session.
@@ -1269,7 +1372,7 @@ public class UserPromptSubmittedHookInput
 /// <summary>
 /// Output for a user-prompt-submitted hook.
 /// </summary>
-public class UserPromptSubmittedHookOutput
+public sealed class UserPromptSubmittedHookOutput
 {
     /// <summary>
     /// Modified prompt to use instead of the original user prompt.
@@ -1290,15 +1393,10 @@ public class UserPromptSubmittedHookOutput
     public bool? SuppressOutput { get; set; }
 }
 
-/// <summary>
-/// Delegate invoked when the user submits a prompt, allowing modification of the prompt.
-/// </summary>
-public delegate Task<UserPromptSubmittedHookOutput?> UserPromptSubmittedHandler(UserPromptSubmittedHookInput input, HookInvocation invocation);
-
 /// <summary>
 /// Input for a session-start hook.
 /// </summary>
-public class SessionStartHookInput
+public sealed class SessionStartHookInput
 {
     /// <summary>
     /// The runtime session ID of the session that triggered the hook.
@@ -1310,7 +1408,8 @@ public class SessionStartHookInput
     /// Unix timestamp in milliseconds when the session started.
     /// </summary>
     [JsonPropertyName("timestamp")]
-    public long Timestamp { get; set; }
+    [JsonConverter(typeof(UnixMillisecondsDateTimeOffsetConverter))]
+    public DateTimeOffset Timestamp { get; set; }
 
     /// <summary>
     /// Current working directory of the session.
@@ -1339,7 +1438,7 @@ public class SessionStartHookInput
 /// <summary>
 /// Output for a session-start hook.
 /// </summary>
-public class SessionStartHookOutput
+public sealed class SessionStartHookOutput
 {
     /// <summary>
     /// Additional context to inject into the session for the language model.
@@ -1354,15 +1453,10 @@ public class SessionStartHookOutput
     public IDictionary<string, object>? ModifiedConfig { get; set; }
 }
 
-/// <summary>
-/// Delegate invoked when a session starts, allowing injection of context or config changes.
-/// </summary>
-public delegate Task<SessionStartHookOutput?> SessionStartHandler(SessionStartHookInput input, HookInvocation invocation);
-
 /// <summary>
 /// Input for a session-end hook.
 /// </summary>
-public class SessionEndHookInput
+public sealed class SessionEndHookInput
 {
     /// <summary>
     /// The runtime session ID of the session that triggered the hook.
@@ -1374,7 +1468,8 @@ public class SessionEndHookInput
     /// Unix timestamp in milliseconds when the session ended.
     /// </summary>
     [JsonPropertyName("timestamp")]
-    public long Timestamp { get; set; }
+    [JsonConverter(typeof(UnixMillisecondsDateTimeOffsetConverter))]
+    public DateTimeOffset Timestamp { get; set; }
 
     /// <summary>
     /// Current working directory of the session.
@@ -1411,7 +1506,7 @@ public class SessionEndHookInput
 /// <summary>
 /// Output for a session-end hook.
 /// </summary>
-public class SessionEndHookOutput
+public sealed class SessionEndHookOutput
 {
     /// <summary>
     /// Whether to suppress the session end output from the conversation.
@@ -1432,15 +1527,10 @@ public class SessionEndHookOutput
     public string? SessionSummary { get; set; }
 }
 
-/// <summary>
-/// Delegate invoked when a session ends, allowing cleanup actions or summary generation.
-/// </summary>
-public delegate Task<SessionEndHookOutput?> SessionEndHandler(SessionEndHookInput input, HookInvocation invocation);
-
 /// <summary>
 /// Input for an error-occurred hook.
 /// </summary>
-public class ErrorOccurredHookInput
+public sealed class ErrorOccurredHookInput
 {
     /// <summary>
     /// The runtime session ID of the session that triggered the hook.
@@ -1452,7 +1542,8 @@ public class ErrorOccurredHookInput
     /// Unix timestamp in milliseconds when the error occurred.
     /// </summary>
     [JsonPropertyName("timestamp")]
-    public long Timestamp { get; set; }
+    [JsonConverter(typeof(UnixMillisecondsDateTimeOffsetConverter))]
+    public DateTimeOffset Timestamp { get; set; }
 
     /// <summary>
     /// Current working directory of the session.
@@ -1488,7 +1579,7 @@ public class ErrorOccurredHookInput
 /// <summary>
 /// Output for an error-occurred hook.
 /// </summary>
-public class ErrorOccurredHookOutput
+public sealed class ErrorOccurredHookOutput
 {
     /// <summary>
     /// Whether to suppress the error output from the conversation.
@@ -1520,45 +1611,40 @@ public class ErrorOccurredHookOutput
     public string? UserNotification { get; set; }
 }
 
-/// <summary>
-/// Delegate invoked when an error occurs, allowing custom error handling strategies.
-/// </summary>
-public delegate Task<ErrorOccurredHookOutput?> ErrorOccurredHandler(ErrorOccurredHookInput input, HookInvocation invocation);
-
 /// <summary>
 /// Hook handlers configuration for a session.
 /// </summary>
-public class SessionHooks
+public sealed class SessionHooks
 {
     /// <summary>
     /// Handler called before a tool is executed.
     /// </summary>
-    public PreToolUseHandler? OnPreToolUse { get; set; }
+    public Func<PreToolUseHookInput, HookInvocation, Task<PreToolUseHookOutput?>>? OnPreToolUse { get; set; }
 
     /// <summary>
     /// Handler called after a tool has been executed.
     /// </summary>
-    public PostToolUseHandler? OnPostToolUse { get; set; }
+    public Func<PostToolUseHookInput, HookInvocation, Task<PostToolUseHookOutput?>>? OnPostToolUse { get; set; }
 
     /// <summary>
     /// Handler called when the user submits a prompt.
     /// </summary>
-    public UserPromptSubmittedHandler? OnUserPromptSubmitted { get; set; }
+    public Func<UserPromptSubmittedHookInput, HookInvocation, Task<UserPromptSubmittedHookOutput?>>? OnUserPromptSubmitted { get; set; }
 
     /// <summary>
     /// Handler called when a session starts.
     /// </summary>
-    public SessionStartHandler? OnSessionStart { get; set; }
+    public Func<SessionStartHookInput, HookInvocation, Task<SessionStartHookOutput?>>? OnSessionStart { get; set; }
 
     /// <summary>
     /// Handler called when a session ends.
     /// </summary>
-    public SessionEndHandler? OnSessionEnd { get; set; }
+    public Func<SessionEndHookInput, HookInvocation, Task<SessionEndHookOutput?>>? OnSessionEnd { get; set; }
 
     /// <summary>
     /// Handler called when an error occurs.
     /// </summary>
-    public ErrorOccurredHandler? OnErrorOccurred { get; set; }
+    public Func<ErrorOccurredHookInput, HookInvocation, Task<ErrorOccurredHookOutput?>>? OnErrorOccurred { get; set; }
 }
 
 /// <summary>
@@ -1604,7 +1690,7 @@ public enum SectionOverrideAction
 /// <summary>
 /// Override operation for a single system prompt section.
 /// </summary>
-public class SectionOverride
+public sealed class SectionOverride
 {
     /// <summary>
     /// The operation to perform on this section. Ignored when Transform is set.
@@ -1657,7 +1743,7 @@ public static class SystemPromptSections
 /// <summary>
 /// Configuration for the system message used in a session.
 /// </summary>
-public class SystemMessageConfig
+public sealed class SystemMessageConfig
 {
     /// <summary>
     /// How the system message is applied (append, replace, or customize).
@@ -1680,7 +1766,7 @@ public class SystemMessageConfig
 /// <summary>
 /// Configuration for a custom model provider.
 /// </summary>
-public class ProviderConfig
+public sealed class ProviderConfig
 {
     /// <summary>
     /// Provider type identifier (e.g., "openai", "azure").
@@ -1730,7 +1816,7 @@ public class ProviderConfig
     /// Well-known model name used by the runtime to look up agent configuration
     /// (tools, prompts, reasoning behavior) and default token limits. Also used
     /// as the wire model when <see cref="WireModel"/> is not set.
-    /// Falls back to <see cref="SessionConfig.Model"/>.
+    /// Falls back to <see cref="SessionConfigBase.Model"/>.
     /// </summary>
     [JsonPropertyName("modelId")]
     public string? ModelId { get; set; }
@@ -1739,7 +1825,7 @@ public class ProviderConfig
     /// Model name sent to the provider API for inference. Use this when the
     /// provider's model name (e.g. an Azure deployment name or a custom
     /// fine-tune name) differs from <see cref="ModelId"/>.
-    /// Falls back to <see cref="ModelId"/>, then <see cref="SessionConfig.Model"/>.
+    /// Falls back to <see cref="ModelId"/>, then <see cref="SessionConfigBase.Model"/>.
     /// </summary>
     [JsonPropertyName("wireModel")]
     public string? WireModel { get; set; }
@@ -1751,7 +1837,7 @@ public class ProviderConfig
     /// exceed this limit.
     /// </summary>
     [JsonPropertyName("maxPromptTokens")]
-    public int? MaxInputTokens { get; set; }
+    public int? MaxPromptTokens { get; set; }
 
     /// <summary>
     /// Overrides the resolved model's default max output tokens. When hit, the
@@ -1764,7 +1850,7 @@ public class ProviderConfig
 /// <summary>
 /// Azure OpenAI-specific provider options.
 /// </summary>
-public class AzureOptions
+public sealed class AzureOptions
 {
     /// <summary>
     /// Azure OpenAI API version to use (e.g., "2024-02-01").
@@ -1805,10 +1891,12 @@ public abstract class McpServerConfig
     private protected McpServerConfig() { }
 
     /// <summary>
-    /// List of tools to include from this server. Empty list means none. Use "*" for all.
+    /// List of tools to include from this server. <c>null</c> (the default)
+    /// means include all tools. An empty list means include none.
     /// </summary>
     [JsonPropertyName("tools")]
-    public IList<string> Tools { get => field ??= []; set; }
+    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+    public IList<string>? Tools { get; set; }
 
     /// <summary>
     /// The server type discriminator.
@@ -1854,7 +1942,7 @@ public sealed class McpStdioServerConfig : McpServerConfig
     /// Working directory for the server process.
     /// </summary>
     [JsonPropertyName("cwd")]
-    public string? Cwd { get; set; }
+    public string? WorkingDirectory { get; set; }
 }
 
 /// <summary>
@@ -1904,7 +1992,7 @@ public sealed class McpHttpServerConfig : McpServerConfig
 /// <summary>
 /// Configuration for a custom agent.
 /// </summary>
-public class CustomAgentConfig
+public sealed class CustomAgentConfig
 {
     /// <summary>
     /// Unique name of the custom agent.
@@ -1952,7 +2040,7 @@ public class CustomAgentConfig
     /// List of skill names to preload into this agent's context.
     /// When set, the full content of each listed skill is eagerly injected into
     /// the agent's context at startup. Skills are resolved by name from the
-    /// session's configured skill directories (<see cref="SessionConfig.SkillDirectories"/>).
+    /// session's configured skill directories (<see cref="SessionConfigBase.SkillDirectories"/>).
     /// When omitted, no skills are injected (opt-in model).
     /// </summary>
     [JsonPropertyName("skills")]
@@ -1972,7 +2060,7 @@ public class CustomAgentConfig
 /// Use <see cref="ExcludedTools"/> to hide specific tools from the default agent
 /// while keeping them available to custom sub-agents.
 /// </summary>
-public class DefaultAgentConfig
+public sealed class DefaultAgentConfig
 {
     /// <summary>
     /// List of tool names to exclude from the default agent.
@@ -1987,7 +2075,7 @@ public class DefaultAgentConfig
 /// When enabled, sessions automatically manage context window limits through background compaction
 /// and persist state to a workspace directory.
 /// </summary>
-public class InfiniteSessionConfig
+public sealed class InfiniteSessionConfig
 {
     /// <summary>
     /// Whether infinite sessions are enabled. Default: true
@@ -2015,7 +2103,7 @@ public class InfiniteSessionConfig
 /// <summary>
 /// GitHub repository metadata to associate with a cloud session.
 /// </summary>
-public class CloudSessionRepository
+public sealed class CloudSessionRepository
 {
     /// <summary>Repository owner.</summary>
     public required string Owner { get; set; }
@@ -2030,7 +2118,7 @@ public class CloudSessionRepository
 /// <summary>
 /// Options for creating a remote session in the cloud.
 /// </summary>
-public class CloudSessionOptions
+public sealed class CloudSessionOptions
 {
     /// <summary>
     /// Optional GitHub repository metadata to associate with the cloud session.
@@ -2039,20 +2127,20 @@ public class CloudSessionOptions
 }
 
 /// <summary>
-/// Configuration options for creating a new Copilot session.
+/// Shared configuration properties for creating or resuming a Copilot session.
+/// Use <see cref="SessionConfig"/> when creating a new session, or
+/// <see cref="ResumeSessionConfig"/> when resuming an existing one.
 /// </summary>
-public class SessionConfig
+public abstract class SessionConfigBase
 {
-    /// <summary>
-    /// Initializes a new instance of the <see cref="SessionConfig"/> class.
-    /// </summary>
-    public SessionConfig() { }
+    /// <summary>Initializes a new instance of the <see cref="SessionConfigBase"/> class.</summary>
+    protected SessionConfigBase() { }
 
     /// <summary>
-    /// Initializes a new instance of the <see cref="SessionConfig"/> class
-    /// by copying the properties of the specified instance.
+    /// Initializes a new instance of <see cref="SessionConfigBase"/> by copying the
+    /// properties of the specified instance.
     /// </summary>
-    protected SessionConfig(SessionConfig? other)
+    protected SessionConfigBase(SessionConfigBase? other)
     {
         if (other is null) return;
 
@@ -2075,20 +2163,18 @@ protected SessionConfig(SessionConfig? other)
             : null;
         Model = other.Model;
         ModelCapabilities = other.ModelCapabilities;
-        OnAutoModeSwitch = other.OnAutoModeSwitch;
+        OnAutoModeSwitchRequest = other.OnAutoModeSwitchRequest;
         OnElicitationRequest = other.OnElicitationRequest;
         OnEvent = other.OnEvent;
-        OnExitPlanMode = other.OnExitPlanMode;
+        OnExitPlanModeRequest = other.OnExitPlanModeRequest;
         OnPermissionRequest = other.OnPermissionRequest;
         OnUserInputRequest = other.OnUserInputRequest;
         Provider = other.Provider;
         EnableSessionTelemetry = other.EnableSessionTelemetry;
         ReasoningEffort = other.ReasoningEffort;
-        CreateSessionFsHandler = other.CreateSessionFsHandler;
+        CreateSessionFsProvider = other.CreateSessionFsProvider;
         GitHubToken = other.GitHubToken;
         RemoteSession = other.RemoteSession;
-        Cloud = other.Cloud;
-        SessionId = other.SessionId;
         SkillDirectories = other.SkillDirectories is not null ? [.. other.SkillDirectories] : null;
         InstructionDirectories = other.InstructionDirectories is not null ? [.. other.InstructionDirectories] : null;
         Streaming = other.Streaming;
@@ -2098,20 +2184,10 @@ protected SessionConfig(SessionConfig? other)
         WorkingDirectory = other.WorkingDirectory;
     }
 
-    /// <summary>
-    /// Optional session identifier; a new ID is generated if not provided.
-    /// </summary>
-    public string? SessionId { get; set; }
-
-    /// <summary>
-    /// Client name to identify the application using the SDK.
-    /// Included in the User-Agent header for API requests.
-    /// </summary>
+    /// <summary>Client name to identify the application using the SDK.</summary>
     public string? ClientName { get; set; }
 
-    /// <summary>
-    /// Model identifier to use for this session (e.g., "gpt-4o").
-    /// </summary>
+    /// <summary>Model identifier to use for this session (e.g., "gpt-4o").</summary>
     public string? Model { get; set; }
 
     /// <summary>
@@ -2121,9 +2197,7 @@ protected SessionConfig(SessionConfig? other)
     /// </summary>
     public string? ReasoningEffort { get; set; }
 
-    /// <summary>
-    /// Per-property overrides for model capabilities, deep-merged over runtime defaults.
-    /// </summary>
+    /// <summary>Per-property overrides for model capabilities, deep-merged over runtime defaults.</summary>
     public ModelCapabilitiesOverride? ModelCapabilities { get; set; }
 
     /// <summary>
@@ -2151,21 +2225,17 @@ protected SessionConfig(SessionConfig? other)
     /// are left for the client to handle via external tool request events.
     /// </summary>
     public ICollection<AIFunctionDeclaration>? Tools { get; set; }
-    /// <summary>
-    /// System message configuration for the session.
-    /// </summary>
+
+    /// <summary>System message configuration for the session.</summary>
     public SystemMessageConfig? SystemMessage { get; set; }
-    /// <summary>
-    /// List of tool names to allow; only these tools will be available when specified.
-    /// </summary>
+
+    /// <summary>List of tool names to allow; only these tools will be available when specified.</summary>
     public IList<string>? AvailableTools { get; set; }
-    /// <summary>
-    /// List of tool names to exclude from the session.
-    /// </summary>
+
+    /// <summary>List of tool names to exclude from the session.</summary>
     public IList<string>? ExcludedTools { get; set; }
-    /// <summary>
-    /// Custom model provider configuration for the session.
-    /// </summary>
+
+    /// <summary>Custom model provider configuration for the session.</summary>
     public ProviderConfig? Provider { get; set; }
 
     /// <summary>
@@ -2179,52 +2249,28 @@ protected SessionConfig(SessionConfig? other)
     /// </summary>
     public bool? EnableSessionTelemetry { get; set; }
 
-    /// <summary>
-    /// Handler for permission requests from the server.
-    /// When provided, the server will call this handler to request permission for operations.
-    /// </summary>
-    public PermissionRequestHandler? OnPermissionRequest { get; set; }
+    /// <summary>Handler for permission requests from the server.</summary>
+    public Func<PermissionRequest, PermissionInvocation, Task<PermissionRequestResult>>? OnPermissionRequest { get; set; }
 
-    /// <summary>
-    /// Handler for user input requests from the agent.
-    /// When provided, enables the ask_user tool for the agent to request user input.
-    /// </summary>
-    public UserInputHandler? OnUserInputRequest { get; set; }
+    /// <summary>Handler for user input requests from the agent.</summary>
+    public Func<UserInputRequest, UserInputInvocation, Task<UserInputResponse>>? OnUserInputRequest { get; set; }
 
-    /// <summary>
-    /// Slash commands registered for this session.
-    /// When the CLI has a TUI, each command appears as <c>/name</c> for the user to invoke.
-    /// The handler is called when the user executes the command.
-    /// </summary>
+    /// <summary>Slash commands registered for this session.</summary>
     public IList<CommandDefinition>? Commands { get; set; }
 
-    /// <summary>
-    /// Handler for elicitation requests from the server or MCP tools.
-    /// When provided, the server will route elicitation requests to this handler
-    /// and report elicitation as a supported capability.
-    /// </summary>
-    public ElicitationHandler? OnElicitationRequest { get; set; }
+    /// <summary>Handler for elicitation requests from the server or MCP tools.</summary>
+    public Func<ElicitationContext, Task<ElicitationResult>>? OnElicitationRequest { get; set; }
 
-    /// <summary>
-    /// Handler for exit-plan-mode requests from the server.
-    /// When provided, the server will route <c>exitPlanMode.request</c> callbacks to this handler.
-    /// </summary>
-    public ExitPlanModeHandler? OnExitPlanMode { get; set; }
+    /// <summary>Handler for exit-plan-mode requests from the server.</summary>
+    public Func<ExitPlanModeRequest, ExitPlanModeInvocation, Task<ExitPlanModeResult>>? OnExitPlanModeRequest { get; set; }
 
-    /// <summary>
-    /// Handler for auto-mode-switch requests from the server.
-    /// When provided, the server will route <c>autoModeSwitch.request</c> callbacks to this handler.
-    /// </summary>
-    public AutoModeSwitchHandler? OnAutoModeSwitch { get; set; }
+    /// <summary>Handler for auto-mode-switch requests from the server.</summary>
+    public Func<AutoModeSwitchRequest, AutoModeSwitchInvocation, Task<AutoModeSwitchResponse>>? OnAutoModeSwitchRequest { get; set; }
 
-    /// <summary>
-    /// Hook handlers for session lifecycle events.
-    /// </summary>
+    /// <summary>Hook handlers for session lifecycle events.</summary>
     public SessionHooks? Hooks { get; set; }
 
-    /// <summary>
-    /// Working directory for the session.
-    /// </summary>
+    /// <summary>Working directory for the session.</summary>
     public string? WorkingDirectory { get; set; }
 
     /// <summary>
@@ -2232,7 +2278,8 @@ protected SessionConfig(SessionConfig? other)
     /// When true, assistant.message_delta and assistant.reasoning_delta events
     /// with deltaContent are sent as the response is generated.
     /// </summary>
-    public bool Streaming { get; set; }
+    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+    public bool? Streaming { get; set; }
 
     /// <summary>
     /// Include sub-agent streaming events in the event stream. When true, streaming
@@ -2251,9 +2298,7 @@ protected SessionConfig(SessionConfig? other)
     /// </summary>
     public IDictionary<string, McpServerConfig>? McpServers { get; set; }
 
-    /// <summary>
-    /// Custom agent configurations for the session.
-    /// </summary>
+    /// <summary>Custom agent configurations for the session.</summary>
     public IList<CustomAgentConfig>? CustomAgents { get; set; }
 
     /// <summary>
@@ -2269,19 +2314,13 @@ protected SessionConfig(SessionConfig? other)
     /// </summary>
     public string? Agent { get; set; }
 
-    /// <summary>
-    /// Directories to load skills from.
-    /// </summary>
+    /// <summary>Directories to load skills from.</summary>
     public IList<string>? SkillDirectories { get; set; }
 
-    /// <summary>
-    /// Additional directories to search for custom instruction files.
-    /// </summary>
+    /// <summary>Additional directories to search for custom instruction files.</summary>
     public IList<string>? InstructionDirectories { get; set; }
 
-    /// <summary>
-    /// List of skill names to disable.
-    /// </summary>
+    /// <summary>List of skill names to disable.</summary>
     public IList<string>? DisabledSkills { get; set; }
 
     /// <summary>
@@ -2291,22 +2330,16 @@ protected SessionConfig(SessionConfig? other)
     public InfiniteSessionConfig? InfiniteSessions { get; set; }
 
     /// <summary>
-    /// Optional event handler that is registered on the session before the
-    /// session.create RPC is issued.
+    /// Optional event handler registered on the session before the session.create / session.resume
+    /// RPC is issued, ensuring early events are delivered.
     /// </summary>
-    /// <remarks>
-    /// Equivalent to calling <see cref="CopilotSession.On"/> immediately
-    /// after creation, but executes earlier in the lifecycle so no events are missed.
-    /// Using this property rather than <see cref="CopilotSession.On"/> guarantees that early events emitted 
-    /// by the CLI during session creation (e.g. session.start) are delivered to the handler.
-    /// </remarks>
-    public SessionEventHandler? OnEvent { get; set; }
+    public Action<SessionEvent>? OnEvent { get; set; }
 
     /// <summary>
     /// Supplies a handler for session filesystem operations.
     /// This is used only when <see cref="CopilotClientOptions.SessionFs"/> is configured.
     /// </summary>
-    public Func<CopilotSession, SessionFsProvider>? CreateSessionFsHandler { get; set; }
+    public Func<CopilotSession, SessionFsProvider>? CreateSessionFsProvider { get; set; }
 
     /// <summary>
     /// GitHub token for per-session authentication.
@@ -2324,6 +2357,30 @@ protected SessionConfig(SessionConfig? other)
     /// </list>
     /// </summary>
     public RemoteSessionMode? RemoteSession { get; set; }
+}
+
+/// <summary>
+/// Configuration options for creating a new Copilot session.
+/// </summary>
+public sealed class SessionConfig : SessionConfigBase
+{
+    /// <summary>Initializes a new instance of the <see cref="SessionConfig"/> class.</summary>
+    public SessionConfig() { }
+
+    /// <summary>
+    /// Initializes a new instance of <see cref="SessionConfig"/> by copying the
+    /// properties of the specified instance.
+    /// </summary>
+    private SessionConfig(SessionConfig? other) : base(other)
+    {
+        if (other is null) return;
+
+        SessionId = other.SessionId;
+        Cloud = other.Cloud;
+    }
+
+    /// <summary>Optional session identifier; a new ID is generated if not provided.</summary>
+    public string? SessionId { get; set; }
 
     /// <summary>
     /// Creates a remote session in the cloud instead of a local session.
@@ -2341,205 +2398,34 @@ protected SessionConfig(SessionConfig? other)
     /// hooks, infinite session configuration, and delegates) are not deep-cloned; the original
     /// and the clone will share those nested objects, and changes to them may affect both.
     /// </remarks>
-    public virtual SessionConfig Clone()
-    {
-        return new(this);
-    }
+    public SessionConfig Clone() => new(this);
 }
 
 /// <summary>
 /// Configuration options for resuming an existing Copilot session.
 /// </summary>
-public class ResumeSessionConfig
+public sealed class ResumeSessionConfig : SessionConfigBase
 {
-    /// <summary>
-    /// Initializes a new instance of the <see cref="ResumeSessionConfig"/> class.
-    /// </summary>
+    /// <summary>Initializes a new instance of the <see cref="ResumeSessionConfig"/> class.</summary>
     public ResumeSessionConfig() { }
 
     /// <summary>
-    /// Initializes a new instance of the <see cref="ResumeSessionConfig"/> class
-    /// by copying the properties of the specified instance.
+    /// Initializes a new instance of <see cref="ResumeSessionConfig"/> by copying the
+    /// properties of the specified instance.
     /// </summary>
-    protected ResumeSessionConfig(ResumeSessionConfig? other)
+    private ResumeSessionConfig(ResumeSessionConfig? other) : base(other)
     {
         if (other is null) return;
 
-        AvailableTools = other.AvailableTools is not null ? [.. other.AvailableTools] : null;
-        ClientName = other.ClientName;
-        Commands = other.Commands is not null ? [.. other.Commands] : null;
-        ConfigDir = other.ConfigDir;
-        CustomAgents = other.CustomAgents is not null ? [.. other.CustomAgents] : null;
-        DefaultAgent = other.DefaultAgent;
-        Agent = other.Agent;
-        DisabledSkills = other.DisabledSkills is not null ? [.. other.DisabledSkills] : null;
-        DisableResume = other.DisableResume;
-        EnableConfigDiscovery = other.EnableConfigDiscovery;
+        SuppressResumeEvent = other.SuppressResumeEvent;
         ContinuePendingWork = other.ContinuePendingWork;
-        ExcludedTools = other.ExcludedTools is not null ? [.. other.ExcludedTools] : null;
-        Hooks = other.Hooks;
-        InfiniteSessions = other.InfiniteSessions;
-        McpServers = other.McpServers is not null
-            ? (other.McpServers is Dictionary<string, McpServerConfig> dict
-                ? new Dictionary<string, McpServerConfig>(dict, dict.Comparer)
-                : new Dictionary<string, McpServerConfig>(other.McpServers))
-            : null;
-        Model = other.Model;
-        ModelCapabilities = other.ModelCapabilities;
-        OnAutoModeSwitch = other.OnAutoModeSwitch;
-        OnElicitationRequest = other.OnElicitationRequest;
-        OnEvent = other.OnEvent;
-        OnExitPlanMode = other.OnExitPlanMode;
-        OnPermissionRequest = other.OnPermissionRequest;
-        OnUserInputRequest = other.OnUserInputRequest;
-        Provider = other.Provider;
-        EnableSessionTelemetry = other.EnableSessionTelemetry;
-        ReasoningEffort = other.ReasoningEffort;
-        CreateSessionFsHandler = other.CreateSessionFsHandler;
-        GitHubToken = other.GitHubToken;
-        RemoteSession = other.RemoteSession;
-        SkillDirectories = other.SkillDirectories is not null ? [.. other.SkillDirectories] : null;
-        InstructionDirectories = other.InstructionDirectories is not null ? [.. other.InstructionDirectories] : null;
-        Streaming = other.Streaming;
-        IncludeSubAgentStreamingEvents = other.IncludeSubAgentStreamingEvents;
-        SystemMessage = other.SystemMessage;
-        Tools = other.Tools is not null ? [.. other.Tools] : null;
-        WorkingDirectory = other.WorkingDirectory;
     }
 
-    /// <summary>
-    /// Client name to identify the application using the SDK.
-    /// Included in the User-Agent header for API requests.
-    /// </summary>
-    public string? ClientName { get; set; }
-
-    /// <summary>
-    /// Model to use for this session. Can change the model when resuming.
-    /// </summary>
-    public string? Model { get; set; }
-
-    /// <summary>
-    /// Custom tool declarations available to the language model during the resumed session.
-    /// Declarations backed by an <see cref="AIFunction"/> are invoked automatically; declarations without one
-    /// are left for the client to handle via external tool request events.
-    /// </summary>
-    public ICollection<AIFunctionDeclaration>? Tools { get; set; }
-
-    /// <summary>
-    /// System message configuration.
-    /// </summary>
-    public SystemMessageConfig? SystemMessage { get; set; }
-
-    /// <summary>
-    /// List of tool names to allow. When specified, only these tools will be available.
-    /// Takes precedence over ExcludedTools.
-    /// </summary>
-    public IList<string>? AvailableTools { get; set; }
-
-    /// <summary>
-    /// List of tool names to disable. All other tools remain available.
-    /// Ignored if AvailableTools is specified.
-    /// </summary>
-    public IList<string>? ExcludedTools { get; set; }
-
-    /// <summary>
-    /// Custom model provider configuration for the resumed session.
-    /// </summary>
-    public ProviderConfig? Provider { get; set; }
-
-    /// <summary>
-    /// Enables or disables internal session telemetry for this session.
-    /// When <c>false</c>, disables session telemetry. When <c>null</c> (the default) or <c>true</c>,
-    /// telemetry is enabled for GitHub-authenticated sessions.
-    /// When a custom <see cref="Provider"/> (BYOK) is configured, session telemetry is
-    /// always disabled regardless of this setting.
-    /// This is independent of <see cref="CopilotClientOptions.Telemetry"/>, which configures
-    /// OpenTelemetry export for observability.
-    /// </summary>
-    public bool? EnableSessionTelemetry { get; set; }
-
-    /// <summary>
-    /// Reasoning effort level for models that support it.
-    /// Valid values: "low", "medium", "high", "xhigh".
-    /// </summary>
-    public string? ReasoningEffort { get; set; }
-
-    /// <summary>
-    /// Per-property overrides for model capabilities, deep-merged over runtime defaults.
-    /// </summary>
-    public ModelCapabilitiesOverride? ModelCapabilities { get; set; }
-
-    /// <summary>
-    /// Handler for permission requests from the server.
-    /// When provided, the server will call this handler to request permission for operations.
-    /// </summary>
-    public PermissionRequestHandler? OnPermissionRequest { get; set; }
-
-    /// <summary>
-    /// Handler for user input requests from the agent.
-    /// When provided, enables the ask_user tool for the agent to request user input.
-    /// </summary>
-    public UserInputHandler? OnUserInputRequest { get; set; }
-
-    /// <summary>
-    /// Slash commands registered for this session.
-    /// When the CLI has a TUI, each command appears as <c>/name</c> for the user to invoke.
-    /// The handler is called when the user executes the command.
-    /// </summary>
-    public IList<CommandDefinition>? Commands { get; set; }
-
-    /// <summary>
-    /// Handler for elicitation requests from the server or MCP tools.
-    /// When provided, the server will route elicitation requests to this handler
-    /// and report elicitation as a supported capability.
-    /// </summary>
-    public ElicitationHandler? OnElicitationRequest { get; set; }
-
-    /// <summary>
-    /// Handler for exit-plan-mode requests from the server.
-    /// When provided, the server will route <c>exitPlanMode.request</c> callbacks to this handler.
-    /// </summary>
-    public ExitPlanModeHandler? OnExitPlanMode { get; set; }
-
-    /// <summary>
-    /// Handler for auto-mode-switch requests from the server.
-    /// When provided, the server will route <c>autoModeSwitch.request</c> callbacks to this handler.
-    /// </summary>
-    public AutoModeSwitchHandler? OnAutoModeSwitch { get; set; }
-
-    /// <summary>
-    /// Hook handlers for session lifecycle events.
-    /// </summary>
-    public SessionHooks? Hooks { get; set; }
-
-    /// <summary>
-    /// Working directory for the session.
-    /// </summary>
-    public string? WorkingDirectory { get; set; }
-
-    /// <summary>
-    /// Override the default configuration directory location.
-    /// </summary>
-    public string? ConfigDir { get; set; }
-
-    /// <summary>
-    /// When <see langword="true"/>, automatically discovers MCP server configurations
-    /// (e.g. <c>.mcp.json</c>, <c>.vscode/mcp.json</c>) and skill directories from
-    /// the working directory and merges them with any explicitly provided
-    /// <see cref="McpServers"/> and <see cref="SkillDirectories"/>, with explicit
-    /// values taking precedence on name collision.
-    /// <para>
-    /// Custom instruction files (<c>.github/copilot-instructions.md</c>, <c>AGENTS.md</c>, etc.)
-    /// are always loaded from the working directory regardless of this setting.
-    /// </para>
-    /// </summary>
-    public bool? EnableConfigDiscovery { get; set; }
-
     /// <summary>
     /// When true, the session.resume event is not emitted.
     /// Default: false (resume event is emitted).
     /// </summary>
-    public bool DisableResume { get; set; }
+    public bool SuppressResumeEvent { get; set; }
 
     /// <summary>
     /// When <see langword="true"/>, instructs the runtime to continue any tool calls
@@ -2548,100 +2434,13 @@ protected ResumeSessionConfig(ResumeSessionConfig? other)
     /// interrupted on resume.
     /// <para>
     /// For permission requests, the runtime re-emits <c>permission.requested</c> so the
-    /// registered <see cref="OnPermissionRequest"/> handler can re-prompt; for external
-    /// tool calls, the consumer is expected to supply the result via the corresponding
-    /// low-level RPC method.
+    /// registered <see cref="SessionConfigBase.OnPermissionRequest"/> handler can re-prompt;
+    /// for external tool calls, the consumer is expected to supply the result via the
+    /// corresponding low-level RPC method.
     /// </para>
     /// </summary>
     public bool? ContinuePendingWork { get; set; }
 
-    /// <summary>
-    /// Enable streaming of assistant message and reasoning chunks.
-    /// When true, assistant.message_delta and assistant.reasoning_delta events
-    /// with deltaContent are sent as the response is generated.
-    /// </summary>
-    public bool Streaming { get; set; }
-
-    /// <summary>
-    /// Include sub-agent streaming events in the event stream. When true, streaming
-    /// delta events from sub-agents (e.g., <c>assistant.message_delta</c>,
-    /// <c>assistant.reasoning_delta</c>, <c>assistant.streaming_delta</c> with
-    /// <c>agentId</c> set) are forwarded to this connection. When false, only
-    /// non-streaming sub-agent events and <c>subagent.*</c> lifecycle events are
-    /// forwarded; streaming deltas from sub-agents are suppressed.
-    /// Default: true.
-    /// </summary>
-    public bool IncludeSubAgentStreamingEvents { get; set; } = true;
-
-    /// <summary>
-    /// MCP server configurations for the session.
-    /// Keys are server names, values are server configurations (<see cref="McpStdioServerConfig"/> or <see cref="McpHttpServerConfig"/>).
-    /// </summary>
-    public IDictionary<string, McpServerConfig>? McpServers { get; set; }
-
-    /// <summary>
-    /// Custom agent configurations for the session.
-    /// </summary>
-    public IList<CustomAgentConfig>? CustomAgents { get; set; }
-
-    /// <summary>
-    /// Configuration for the default agent (the built-in agent that handles turns when no custom agent is selected).
-    /// Use <see cref="DefaultAgentConfig.ExcludedTools"/> to hide specific tools from the default agent
-    /// while keeping them available to custom sub-agents.
-    /// </summary>
-    public DefaultAgentConfig? DefaultAgent { get; set; }
-
-    /// <summary>
-    /// Name of the custom agent to activate when the session starts.
-    /// Must match the <see cref="CustomAgentConfig.Name"/> of one of the agents in <see cref="CustomAgents"/>.
-    /// </summary>
-    public string? Agent { get; set; }
-
-    /// <summary>
-    /// Directories to load skills from.
-    /// </summary>
-    public IList<string>? SkillDirectories { get; set; }
-
-    /// <summary>
-    /// Additional directories to search for custom instruction files.
-    /// </summary>
-    public IList<string>? InstructionDirectories { get; set; }
-
-    /// <summary>
-    /// List of skill names to disable.
-    /// </summary>
-    public IList<string>? DisabledSkills { get; set; }
-
-    /// <summary>
-    /// Infinite session configuration for persistent workspaces and automatic compaction.
-    /// </summary>
-    public InfiniteSessionConfig? InfiniteSessions { get; set; }
-
-    /// <summary>
-    /// Optional event handler registered before the session.resume RPC is issued,
-    /// ensuring early events are delivered. See <see cref="SessionConfig.OnEvent"/>.
-    /// </summary>
-    public SessionEventHandler? OnEvent { get; set; }
-
-    /// <summary>
-    /// Supplies a handler for session filesystem operations.
-    /// This is used only when <see cref="CopilotClientOptions.SessionFs"/> is configured.
-    /// </summary>
-    public Func<CopilotSession, SessionFsProvider>? CreateSessionFsHandler { get; set; }
-
-    /// <summary>
-    /// GitHub token for per-session authentication.
-    /// When provided, the runtime resolves this token into a full GitHub identity
-    /// and stores it on the session for content exclusion, model routing, and quota checks.
-    /// </summary>
-    public string? GitHubToken { get; set; }
-
-    /// <summary>
-    /// Per-session remote behavior control.
-    /// See <see cref="SessionConfig.RemoteSession"/> for details.
-    /// </summary>
-    public RemoteSessionMode? RemoteSession { get; set; }
-
     /// <summary>
     /// Creates a shallow clone of this <see cref="ResumeSessionConfig"/> instance.
     /// </summary>
@@ -2652,16 +2451,13 @@ protected ResumeSessionConfig(ResumeSessionConfig? other)
     /// hooks, infinite session configuration, and delegates) are not deep-cloned; the original
     /// and the clone will share those nested objects, and changes to them may affect both.
     /// </remarks>
-    public virtual ResumeSessionConfig Clone()
-    {
-        return new(this);
-    }
+    public ResumeSessionConfig Clone() => new(this);
 }
 
 /// <summary>
 /// Options for sending a message in a Copilot session.
 /// </summary>
-public class MessageOptions
+public sealed class MessageOptions
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="MessageOptions"/> class.
@@ -2672,7 +2468,7 @@ public MessageOptions() { }
     /// Initializes a new instance of the <see cref="MessageOptions"/> class
     /// by copying the properties of the specified instance.
     /// </summary>
-    protected MessageOptions(MessageOptions? other)
+    private MessageOptions(MessageOptions? other)
     {
         if (other is null) return;
 
@@ -2710,21 +2506,16 @@ protected MessageOptions(MessageOptions? other)
     /// Other reference-type properties (for example attachment items) are not deep-cloned;
     /// the original and the clone will share those nested objects.
     /// </remarks>
-    public virtual MessageOptions Clone()
+    public MessageOptions Clone()
     {
         return new(this);
     }
 }
 
-/// <summary>
-/// Delegate for handling session events emitted during a Copilot session.
-/// </summary>
-public delegate void SessionEventHandler(SessionEvent sessionEvent);
-
 /// <summary>
 /// Working directory context for a session.
 /// </summary>
-public class SessionContext
+public sealed class SessionContext
 {
     /// <summary>Working directory where the session was created.</summary>
     public string Cwd { get; set; } = string.Empty;
@@ -2739,10 +2530,10 @@ public class SessionContext
 /// <summary>
 /// Filter options for listing sessions.
 /// </summary>
-public class SessionListFilter
+public sealed class SessionListFilter
 {
-    /// <summary>Filter by exact cwd match.</summary>
-    public string? Cwd { get; set; }
+    /// <summary>Filter by exact working directory match.</summary>
+    public string? WorkingDirectory { get; set; }
     /// <summary>Filter by git root.</summary>
     public string? GitRoot { get; set; }
     /// <summary>Filter by repository (owner/repo format).</summary>
@@ -2754,7 +2545,7 @@ public class SessionListFilter
 /// <summary>
 /// Metadata describing a Copilot session.
 /// </summary>
-public class SessionMetadata
+public sealed class SessionMetadata
 {
     /// <summary>
     /// Unique identifier of the session.
@@ -2763,11 +2554,11 @@ public class SessionMetadata
     /// <summary>
     /// Time when the session was created.
     /// </summary>
-    public DateTime StartTime { get; set; }
+    public DateTimeOffset StartTime { get; set; }
     /// <summary>
     /// Time when the session was last modified.
     /// </summary>
-    public DateTime ModifiedTime { get; set; }
+    public DateTimeOffset ModifiedTime { get; set; }
     /// <summary>
     /// Human-readable summary of the session.
     /// </summary>
@@ -2788,7 +2579,7 @@ internal class PingRequest
 /// <summary>
 /// Response from a server ping request.
 /// </summary>
-public class PingResponse
+public sealed class PingResponse
 {
     /// <summary>
     /// Echo of the ping message.
@@ -2807,7 +2598,7 @@ public class PingResponse
 /// <summary>
 /// Response from status.get
 /// </summary>
-public class GetStatusResponse
+public sealed class GetStatusResponse
 {
     /// <summary>Package version (e.g., "1.0.0")</summary>
     [JsonPropertyName("version")]
@@ -2821,7 +2612,7 @@ public class GetStatusResponse
 /// <summary>
 /// Response from auth.getStatus
 /// </summary>
-public class GetAuthStatusResponse
+public sealed class GetAuthStatusResponse
 {
     /// <summary>Whether the user is authenticated</summary>
     [JsonPropertyName("isAuthenticated")]
@@ -2857,7 +2648,7 @@ public class GetAuthStatusResponse
 /// <summary>
 /// Model vision-specific limits
 /// </summary>
-public class ModelVisionLimits
+public sealed class ModelVisionLimits
 {
     /// <summary>
     /// List of supported image MIME types (e.g., "image/png", "image/jpeg").
@@ -2881,7 +2672,7 @@ public class ModelVisionLimits
 /// <summary>
 /// Model limits
 /// </summary>
-public class ModelLimits
+public sealed class ModelLimits
 {
     /// <summary>
     /// Maximum number of tokens allowed in the prompt.
@@ -2905,7 +2696,7 @@ public class ModelLimits
 /// <summary>
 /// Model support flags
 /// </summary>
-public class ModelSupports
+public sealed class ModelSupports
 {
     /// <summary>
     /// Whether this model supports image/vision inputs.
@@ -2923,7 +2714,7 @@ public class ModelSupports
 /// <summary>
 /// Model capabilities and limits
 /// </summary>
-public class ModelCapabilities
+public sealed class ModelCapabilities
 {
     /// <summary>
     /// Feature support flags for the model.
@@ -2941,7 +2732,7 @@ public class ModelCapabilities
 /// <summary>
 /// Model policy state
 /// </summary>
-public class ModelPolicy
+public sealed class ModelPolicy
 {
     /// <summary>
     /// Policy state of the model (e.g., "enabled", "disabled").
@@ -2959,7 +2750,7 @@ public class ModelPolicy
 /// <summary>
 /// Model billing information
 /// </summary>
-public class ModelBilling
+public sealed class ModelBilling
 {
     /// <summary>
     /// Billing cost multiplier relative to the base model rate.
@@ -2971,7 +2762,7 @@ public class ModelBilling
 /// <summary>
 /// Information about an available model
 /// </summary>
-public class ModelInfo
+public sealed class ModelInfo
 {
     /// <summary>Model identifier (e.g., "claude-sonnet-4.5")</summary>
     [JsonPropertyName("id")]
@@ -3005,7 +2796,7 @@ public class ModelInfo
 /// <summary>
 /// Response from models.list
 /// </summary>
-public class GetModelsResponse
+public sealed class GetModelsResponse
 {
     /// <summary>
     /// List of available models.
@@ -3019,38 +2810,21 @@ public class GetModelsResponse
 // ============================================================================
 
 /// <summary>
-/// Types of session lifecycle events
-/// </summary>
-public static class SessionLifecycleEventTypes
-{
-    /// <summary>A new session was created.</summary>
-    public const string Created = "session.created";
-    /// <summary>A session was deleted.</summary>
-    public const string Deleted = "session.deleted";
-    /// <summary>A session was updated.</summary>
-    public const string Updated = "session.updated";
-    /// <summary>A session was brought to the foreground.</summary>
-    public const string Foreground = "session.foreground";
-    /// <summary>A session was moved to the background.</summary>
-    public const string Background = "session.background";
-}
-
-/// <summary>
-/// Metadata for session lifecycle events
+/// Metadata for session lifecycle events.
 /// </summary>
-public class SessionLifecycleEventMetadata
+public sealed class SessionLifecycleEventMetadata
 {
     /// <summary>
-    /// ISO 8601 timestamp when the session was created.
+    /// Timestamp when the session was created.
     /// </summary>
     [JsonPropertyName("startTime")]
-    public string StartTime { get; set; } = string.Empty;
+    public DateTimeOffset StartTime { get; set; }
 
     /// <summary>
-    /// ISO 8601 timestamp when the session was last modified.
+    /// Timestamp when the session was last modified.
     /// </summary>
     [JsonPropertyName("modifiedTime")]
-    public string ModifiedTime { get; set; } = string.Empty;
+    public DateTimeOffset ModifiedTime { get; set; }
 
     /// <summary>
     /// Human-readable summary of the session.
@@ -3060,12 +2834,20 @@ public class SessionLifecycleEventMetadata
 }
 
 /// <summary>
-/// Session lifecycle event notification
+/// Session lifecycle event notification. Use derived types
+/// (<see cref="SessionCreatedEvent"/>, <see cref="SessionDeletedEvent"/>,
+/// <see cref="SessionUpdatedEvent"/>, <see cref="SessionForegroundEvent"/>,
+/// <see cref="SessionBackgroundEvent"/>) for known kinds. The base type is
+/// instantiated when the runtime emits an event kind not known to this SDK
+/// version, so consumers can still inspect <see cref="Type"/> for forward
+/// compatibility.
 /// </summary>
 public class SessionLifecycleEvent
 {
     /// <summary>
-    /// Type of lifecycle event (see <see cref="SessionLifecycleEventTypes"/>).
+    /// Wire-format type discriminator (e.g., <c>"session.created"</c>). Useful
+    /// when the runtime emits an event kind not yet known to this SDK; for
+    /// known kinds, prefer pattern-matching on the derived type instead.
     /// </summary>
     [JsonPropertyName("type")]
     public string Type { get; set; } = string.Empty;
@@ -3083,10 +2865,25 @@ public class SessionLifecycleEvent
     public SessionLifecycleEventMetadata? Metadata { get; set; }
 }
 
+/// <summary>Raised when a new session is created.</summary>
+public sealed class SessionCreatedEvent : SessionLifecycleEvent { }
+
+/// <summary>Raised when a session is deleted.</summary>
+public sealed class SessionDeletedEvent : SessionLifecycleEvent { }
+
+/// <summary>Raised when a session's metadata is updated.</summary>
+public sealed class SessionUpdatedEvent : SessionLifecycleEvent { }
+
+/// <summary>Raised when a session is brought to the foreground (TUI+server mode).</summary>
+public sealed class SessionForegroundEvent : SessionLifecycleEvent { }
+
+/// <summary>Raised when a session moves to the background (TUI+server mode).</summary>
+public sealed class SessionBackgroundEvent : SessionLifecycleEvent { }
+
 /// <summary>
 /// Response from session.getForeground
 /// </summary>
-public class GetForegroundSessionResponse
+public sealed class GetForegroundSessionResponse
 {
     /// <summary>
     /// Identifier of the current foreground session, or null if none.
@@ -3104,7 +2901,7 @@ public class GetForegroundSessionResponse
 /// <summary>
 /// Response from session.setForeground
 /// </summary>
-public class SetForegroundSessionResponse
+public sealed class SetForegroundSessionResponse
 {
     /// <summary>
     /// Whether the foreground session was set successfully.
@@ -3122,7 +2919,7 @@ public class SetForegroundSessionResponse
 /// <summary>
 /// Content data for a single system prompt section in a transform RPC call.
 /// </summary>
-public class SystemMessageTransformSection
+public sealed class SystemMessageTransformSection
 {
     /// <summary>
     /// The content of the section.
@@ -3134,7 +2931,7 @@ public class SystemMessageTransformSection
 /// <summary>
 /// Response to a systemMessage.transform RPC call.
 /// </summary>
-public class SystemMessageTransformRpcResponse
+public sealed class SystemMessageTransformRpcResponse
 {
     /// <summary>
     /// The transformed sections keyed by section identifier.
@@ -3182,8 +2979,12 @@ public class SystemMessageTransformRpcResponse
 [JsonSerializable(typeof(SetForegroundSessionResponse))]
 [JsonSerializable(typeof(SystemMessageConfig))]
 [JsonSerializable(typeof(ToolBinaryResult))]
+[JsonSerializable(typeof(ToolBinaryResultType))]
 [JsonSerializable(typeof(ToolInvocation))]
 [JsonSerializable(typeof(ToolResultObject))]
 [JsonSerializable(typeof(JsonElement))]
 [JsonSerializable(typeof(JsonElement?))]
+[JsonSerializable(typeof(object))]
+[JsonSerializable(typeof(Dictionary<string, object>))]
+[JsonSerializable(typeof(string[]))]
 internal partial class TypesJsonContext : JsonSerializerContext;
diff --git a/dotnet/src/UnixMillisecondsDateTimeOffsetConverter.cs b/dotnet/src/UnixMillisecondsDateTimeOffsetConverter.cs
new file mode 100644
index 000000000..4b8fcc361
--- /dev/null
+++ b/dotnet/src/UnixMillisecondsDateTimeOffsetConverter.cs
@@ -0,0 +1,22 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *--------------------------------------------------------------------------------------------*/
+
+using System.ComponentModel;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace GitHub.Copilot;
+
+/// <summary>Converts between JSON numeric milliseconds-since-Unix-epoch and <see cref="DateTimeOffset"/>.</summary>
+[EditorBrowsable(EditorBrowsableState.Never)]
+public sealed class UnixMillisecondsDateTimeOffsetConverter : JsonConverter<DateTimeOffset>
+{
+    /// <inheritdoc />
+    public override DateTimeOffset Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) =>
+        DateTimeOffset.FromUnixTimeMilliseconds(reader.GetInt64());
+
+    /// <inheritdoc />
+    public override void Write(Utf8JsonWriter writer, DateTimeOffset value, JsonSerializerOptions options) =>
+        writer.WriteNumberValue(value.ToUnixTimeMilliseconds());
+}
diff --git a/dotnet/test/ConnectionTokenTests.cs b/dotnet/test/ConnectionTokenTests.cs
index dc6f115ba..524ff2586 100644
--- a/dotnet/test/ConnectionTokenTests.cs
+++ b/dotnet/test/ConnectionTokenTests.cs
@@ -2,10 +2,10 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test;
+namespace GitHub.Copilot.Test;
 
 /// <summary>
 /// Custom fixture that spawns a CLI in TCP mode with an explicit connection token, so
@@ -22,14 +22,11 @@ public class ConnectionTokenTestFixture : IAsyncLifetime
     public async Task InitializeAsync()
     {
         Ctx = await E2ETestContext.CreateAsync();
-        GoodClient = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions
-        {
-            TcpConnectionToken = Token,
-        });
+        GoodClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForTcp(connectionToken: Token) });
 
         await GoodClient.StartAsync();
-        Port = GoodClient.ActualPort
-            ?? throw new InvalidOperationException("GoodClient is not using TCP mode; ActualPort is null");
+        Port = GoodClient.RuntimePort
+            ?? throw new InvalidOperationException("GoodClient is not using TCP mode; RuntimePort is null");
     }
 
     public async Task DisposeAsync()
@@ -62,11 +59,7 @@ public async Task Connects_With_The_Matching_Token()
     [Fact]
     public async Task Rejects_A_Wrong_Token()
     {
-        var wrongClient = new CopilotClient(new CopilotClientOptions
-        {
-            CliUrl = $"localhost:{_fixture.Port}",
-            TcpConnectionToken = "wrong",
-        });
+        var wrongClient = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri($"localhost:{_fixture.Port}", connectionToken: "wrong") });
 
         try
         {
@@ -83,10 +76,7 @@ public async Task Rejects_A_Wrong_Token()
     [Fact]
     public async Task Rejects_A_Missing_Token_When_One_Is_Required()
     {
-        var noTokenClient = new CopilotClient(new CopilotClientOptions
-        {
-            CliUrl = $"localhost:{_fixture.Port}",
-        });
+        var noTokenClient = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri($"localhost:{_fixture.Port}") });
 
         try
         {
diff --git a/dotnet/test/E2E/AbortE2ETests.cs b/dotnet/test/E2E/AbortE2ETests.cs
index 009ca1e29..ea24610b7 100644
--- a/dotnet/test/E2E/AbortE2ETests.cs
+++ b/dotnet/test/E2E/AbortE2ETests.cs
@@ -7,7 +7,7 @@
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Verifies that <see cref="CopilotSession.AbortAsync"/> cleanly interrupts an active
@@ -25,7 +25,7 @@ public async Task Should_Abort_During_Active_Streaming()
         var firstDeltaReceived = new TaskCompletionSource<AssistantMessageDeltaEvent>(TaskCreationOptions.RunContinuationsAsynchronously);
         var allEvents = new List<SessionEvent>();
 
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             lock (allEvents) { allEvents.Add(evt); }
             if (evt is AssistantMessageDeltaEvent delta)
@@ -60,7 +60,7 @@ public async Task Should_Abort_During_Active_Streaming()
         // recovery message rather than racing against a late idle from the
         // aborted streaming turn.
         var recoveryReceived = new TaskCompletionSource<AssistantMessageEvent>(TaskCreationOptions.RunContinuationsAsynchronously);
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             if (evt is AssistantMessageEvent msg && (msg.Data.Content?.Contains("abort_recovery_ok") == true))
             {
@@ -109,7 +109,7 @@ public async Task Should_Abort_During_Active_Tool_Execution()
 
         // Session should be usable after abort — verify by listening for the right event
         var recoveryReceived = new TaskCompletionSource<AssistantMessageEvent>(TaskCreationOptions.RunContinuationsAsynchronously);
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             if (evt is AssistantMessageEvent msg && (msg.Data.Content?.Contains("tool_abort_recovery_ok") == true))
             {
diff --git a/dotnet/test/E2E/AskUserE2ETests.cs b/dotnet/test/E2E/AskUserE2ETests.cs
index cd79652d0..62faff367 100644
--- a/dotnet/test/E2E/AskUserE2ETests.cs
+++ b/dotnet/test/E2E/AskUserE2ETests.cs
@@ -2,11 +2,11 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class AskUserE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "ask_user", output)
 {
diff --git a/dotnet/test/E2E/BuiltinToolsE2ETests.cs b/dotnet/test/E2E/BuiltinToolsE2ETests.cs
index 76bbcf190..863331e9d 100644
--- a/dotnet/test/E2E/BuiltinToolsE2ETests.cs
+++ b/dotnet/test/E2E/BuiltinToolsE2ETests.cs
@@ -5,7 +5,7 @@
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Smoke coverage for the Copilot CLI built-in tools (bash, view, edit, create_file,
diff --git a/dotnet/test/E2E/ClientE2ETests.cs b/dotnet/test/E2E/ClientE2ETests.cs
index b8885fb2d..4e1ea2ddc 100644
--- a/dotnet/test/E2E/ClientE2ETests.cs
+++ b/dotnet/test/E2E/ClientE2ETests.cs
@@ -1,11 +1,11 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 // These tests bypass E2ETestBase because they are about how the CLI subprocess is started
 // Other test classes should instead inherit from E2ETestBase
@@ -16,19 +16,16 @@ public class ClientE2ETests
     [InlineData(false)]  // TCP transport
     public async Task Should_Start_And_Connect_To_Server(bool useStdio)
     {
-        using var client = new CopilotClient(new CopilotClientOptions { UseStdio = useStdio });
+        using var client = new CopilotClient(new CopilotClientOptions { Connection = useStdio ? RuntimeConnection.ForStdio() : RuntimeConnection.ForTcp() });
 
         try
         {
             await client.StartAsync();
-            Assert.Equal(ConnectionState.Connected, client.State);
-
             var pong = await client.PingAsync("test message");
             Assert.Equal("pong: test message", pong.Message);
             Assert.NotEqual(default, pong.Timestamp);
 
             await client.StopAsync();
-            Assert.Equal(ConnectionState.Disconnected, client.State);
         }
         finally
         {
@@ -41,12 +38,10 @@ public async Task Should_Start_And_Connect_To_Server(bool useStdio)
     [InlineData(false)]  // TCP transport
     public async Task Should_Force_Stop_Without_Cleanup(bool useStdio)
     {
-        using var client = new CopilotClient(new CopilotClientOptions { UseStdio = useStdio });
+        using var client = new CopilotClient(new CopilotClientOptions { Connection = useStdio ? RuntimeConnection.ForStdio() : RuntimeConnection.ForTcp() });
 
         await client.CreateSessionAsync(new SessionConfig { OnPermissionRequest = PermissionHandler.ApproveAll });
         await client.ForceStopAsync();
-
-        Assert.Equal(ConnectionState.Disconnected, client.State);
     }
 
     [Theory]
@@ -54,7 +49,7 @@ public async Task Should_Force_Stop_Without_Cleanup(bool useStdio)
     [InlineData(false)]  // TCP transport
     public async Task Should_Get_Status_With_Version_And_Protocol_Info(bool useStdio)
     {
-        using var client = new CopilotClient(new CopilotClientOptions { UseStdio = useStdio });
+        using var client = new CopilotClient(new CopilotClientOptions { Connection = useStdio ? RuntimeConnection.ForStdio() : RuntimeConnection.ForTcp() });
 
         try
         {
@@ -78,7 +73,7 @@ public async Task Should_Get_Status_With_Version_And_Protocol_Info(bool useStdio
     [InlineData(false)]  // TCP transport
     public async Task Should_Get_Auth_Status(bool useStdio)
     {
-        using var client = new CopilotClient(new CopilotClientOptions { UseStdio = useStdio });
+        using var client = new CopilotClient(new CopilotClientOptions { Connection = useStdio ? RuntimeConnection.ForStdio() : RuntimeConnection.ForTcp() });
 
         try
         {
@@ -105,7 +100,7 @@ public async Task Should_Get_Auth_Status(bool useStdio)
     [InlineData(false)]  // TCP transport
     public async Task Should_List_Models_When_Authenticated(bool useStdio)
     {
-        using var client = new CopilotClient(new CopilotClientOptions { UseStdio = useStdio });
+        using var client = new CopilotClient(new CopilotClientOptions { Connection = useStdio ? RuntimeConnection.ForStdio() : RuntimeConnection.ForTcp() });
 
         try
         {
@@ -143,7 +138,7 @@ public async Task Should_List_Models_When_Authenticated(bool useStdio)
     [InlineData(false)]  // TCP transport
     public async Task Should_Not_Throw_When_Disposing_Session_After_Stopping_Client(bool useStdio)
     {
-        await using var client = new CopilotClient(new CopilotClientOptions { UseStdio = useStdio });
+        await using var client = new CopilotClient(new CopilotClientOptions { Connection = useStdio ? RuntimeConnection.ForStdio() : RuntimeConnection.ForTcp() });
         await using var session = await client.CreateSessionAsync(new SessionConfig { OnPermissionRequest = PermissionHandler.ApproveAll });
 
         await client.StopAsync();
@@ -156,8 +151,9 @@ public async Task Should_Report_Error_With_Stderr_When_CLI_Fails_To_Start(bool u
     {
         var client = new CopilotClient(new CopilotClientOptions
         {
-            CliArgs = ["--nonexistent-flag-for-testing"],
-            UseStdio = useStdio
+            Connection = useStdio
+                ? RuntimeConnection.ForStdio(args: ["--nonexistent-flag-for-testing"])
+                : RuntimeConnection.ForTcp(args: ["--nonexistent-flag-for-testing"])
         });
 
         var ex = await Assert.ThrowsAsync<IOException>(() => client.StartAsync());
@@ -184,7 +180,7 @@ public async Task Should_Report_Error_With_Stderr_When_CLI_Fails_To_Start(bool u
     [InlineData(false)]  // TCP transport
     public async Task Should_Allow_CreateSession_Called_Without_PermissionHandler(bool useStdio)
     {
-        await using var client = new CopilotClient(new CopilotClientOptions { UseStdio = useStdio });
+        await using var client = new CopilotClient(new CopilotClientOptions { Connection = useStdio ? RuntimeConnection.ForStdio() : RuntimeConnection.ForTcp() });
         await using var session = await client.CreateSessionAsync(new SessionConfig());
 
         Assert.NotNull(session.SessionId);
@@ -196,19 +192,18 @@ public async Task Should_Allow_ResumeSession_Called_Without_PermissionHandler()
         const string connectionToken = "client-e2e-resume-token";
 
         await using var ctx = await E2ETestContext.CreateAsync();
-        await using var client = ctx.CreateClient(useStdio: false, options: new CopilotClientOptions
+        await using var client = ctx.CreateClient(options: new CopilotClientOptions
         {
-            TcpConnectionToken = connectionToken,
+            Connection = RuntimeConnection.ForTcp(connectionToken: connectionToken),
         });
         await using var originalSession = await client.CreateSessionAsync(new SessionConfig());
 
-        var port = client.ActualPort
+        var port = client.RuntimePort
             ?? throw new InvalidOperationException("Client must be using TCP transport to support multi-client resume.");
 
         await using var resumeClient = ctx.CreateClient(options: new CopilotClientOptions
         {
-            CliUrl = $"localhost:{port}",
-            TcpConnectionToken = connectionToken,
+            Connection = RuntimeConnection.ForUri($"localhost:{port}", connectionToken: connectionToken),
         });
         await using var resumedSession = await resumeClient.ResumeSessionAsync(originalSession.SessionId, new());
 
@@ -237,7 +232,7 @@ public async Task ListModels_WithCustomHandler_CallsHandler(bool useStdio)
         var callCount = 0;
         await using var client = new CopilotClient(new CopilotClientOptions
         {
-            UseStdio = useStdio,
+            Connection = useStdio ? RuntimeConnection.ForStdio() : RuntimeConnection.ForTcp(),
             OnListModels = (ct) =>
             {
                 callCount++;
@@ -274,7 +269,7 @@ public async Task ListModels_WithCustomHandler_CachesResults(bool useStdio)
         var callCount = 0;
         await using var client = new CopilotClient(new CopilotClientOptions
         {
-            UseStdio = useStdio,
+            Connection = useStdio ? RuntimeConnection.ForStdio() : RuntimeConnection.ForTcp(),
             OnListModels = (ct) =>
             {
                 callCount++;
@@ -310,7 +305,7 @@ public async Task ListModels_WithCustomHandler_WorksWithoutStart(bool useStdio)
         var callCount = 0;
         await using var client = new CopilotClient(new CopilotClientOptions
         {
-            UseStdio = useStdio,
+            Connection = useStdio ? RuntimeConnection.ForStdio() : RuntimeConnection.ForTcp(),
             OnListModels = (ct) =>
             {
                 callCount++;
diff --git a/dotnet/test/E2E/ClientLifecycleE2ETests.cs b/dotnet/test/E2E/ClientLifecycleE2ETests.cs
index 7026093f8..4b09c695d 100644
--- a/dotnet/test/E2E/ClientLifecycleE2ETests.cs
+++ b/dotnet/test/E2E/ClientLifecycleE2ETests.cs
@@ -1,12 +1,12 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
+using GitHub.Copilot.Rpc;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class ClientLifecycleE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "client_lifecycle", output)
@@ -15,9 +15,9 @@ public class ClientLifecycleE2ETests(E2ETestFixture fixture, ITestOutputHelper o
     public async Task Should_Receive_Session_Created_Lifecycle_Event()
     {
         var created = new TaskCompletionSource<SessionLifecycleEvent>(TaskCreationOptions.RunContinuationsAsynchronously);
-        using var subscription = Client.On(evt =>
+        using var subscription = Client.OnLifecycle<SessionLifecycleEvent>(evt =>
         {
-            if (evt.Type == SessionLifecycleEventTypes.Created)
+            if (evt is SessionCreatedEvent)
             {
                 created.TrySetResult(evt);
             }
@@ -26,7 +26,7 @@ public async Task Should_Receive_Session_Created_Lifecycle_Event()
         await using var session = await CreateSessionAsync();
         var evt = await created.Task.WaitAsync(TimeSpan.FromSeconds(10));
 
-        Assert.Equal(SessionLifecycleEventTypes.Created, evt.Type);
+        Assert.IsType<SessionCreatedEvent>(evt);
         Assert.Equal(session.SessionId, evt.SessionId);
     }
 
@@ -34,12 +34,12 @@ public async Task Should_Receive_Session_Created_Lifecycle_Event()
     public async Task Should_Filter_Session_Lifecycle_Events_By_Type()
     {
         var created = new TaskCompletionSource<SessionLifecycleEvent>(TaskCreationOptions.RunContinuationsAsynchronously);
-        using var subscription = Client.On(SessionLifecycleEventTypes.Created, evt => created.TrySetResult(evt));
+        using var subscription = Client.OnLifecycle<SessionCreatedEvent>(evt => created.TrySetResult(evt));
 
         await using var session = await CreateSessionAsync();
         var evt = await created.Task.WaitAsync(TimeSpan.FromSeconds(10));
 
-        Assert.Equal(SessionLifecycleEventTypes.Created, evt.Type);
+        Assert.IsType<SessionCreatedEvent>(evt);
         Assert.Equal(session.SessionId, evt.SessionId);
     }
 
@@ -48,9 +48,9 @@ public async Task Disposing_Lifecycle_Subscription_Stops_Receiving_Events()
     {
         var count = 0;
         var created = new TaskCompletionSource<SessionLifecycleEvent>(TaskCreationOptions.RunContinuationsAsynchronously);
-        var subscription = Client.On(_ => Interlocked.Increment(ref count));
+        var subscription = Client.OnLifecycle<SessionLifecycleEvent>(_ => Interlocked.Increment(ref count));
         subscription.Dispose();
-        using var activeSubscription = Client.On(SessionLifecycleEventTypes.Created, evt => created.TrySetResult(evt));
+        using var activeSubscription = Client.OnLifecycle<SessionCreatedEvent>(evt => created.TrySetResult(evt));
 
         await using var session = await CreateSessionAsync();
         var evt = await created.Task.WaitAsync(TimeSpan.FromSeconds(10));
@@ -66,9 +66,6 @@ public async Task Dispose_Disconnects_Client_And_Disposes_Rpc_Surface(bool useAs
     {
         var client = Ctx.CreateClient();
         await client.StartAsync();
-
-        Assert.Equal(ConnectionState.Connected, client.State);
-
         if (useAsyncDispose)
         {
             await client.DisposeAsync();
@@ -77,8 +74,6 @@ public async Task Dispose_Disconnects_Client_And_Disposes_Rpc_Surface(bool useAs
         {
             client.Dispose();
         }
-
-        Assert.Equal(ConnectionState.Disconnected, client.State);
         Assert.Throws<ObjectDisposedException>(() => client.Rpc);
     }
 
@@ -88,7 +83,7 @@ public async Task Should_Receive_Session_Updated_Lifecycle_Event_For_Non_Ephemer
         await using var session = await CreateSessionAsync();
 
         var updated = new TaskCompletionSource<SessionLifecycleEvent>(TaskCreationOptions.RunContinuationsAsynchronously);
-        using var subscription = Client.On(SessionLifecycleEventTypes.Updated, evt =>
+        using var subscription = Client.OnLifecycle<SessionUpdatedEvent>(evt =>
         {
             if (string.Equals(evt.SessionId, session.SessionId, StringComparison.Ordinal))
             {
@@ -101,7 +96,7 @@ public async Task Should_Receive_Session_Updated_Lifecycle_Event_For_Non_Ephemer
         await session.Rpc.Mode.SetAsync(SessionMode.Plan);
 
         var evt = await updated.Task.WaitAsync(TimeSpan.FromSeconds(15));
-        Assert.Equal(SessionLifecycleEventTypes.Updated, evt.Type);
+        Assert.IsType<SessionUpdatedEvent>(evt);
         Assert.Equal(session.SessionId, evt.SessionId);
     }
 
@@ -118,7 +113,7 @@ public async Task Should_Receive_Session_Deleted_Lifecycle_Event_When_Deleted()
         await session.SendAndWaitAsync(new MessageOptions { Prompt = "Say SESSION_DELETED_OK exactly." });
 
         var deleted = new TaskCompletionSource<SessionLifecycleEvent>(TaskCreationOptions.RunContinuationsAsynchronously);
-        using var subscription = Client.On(SessionLifecycleEventTypes.Deleted, evt =>
+        using var subscription = Client.OnLifecycle<SessionDeletedEvent>(evt =>
         {
             if (string.Equals(evt.SessionId, sessionId, StringComparison.Ordinal))
             {
@@ -132,7 +127,7 @@ public async Task Should_Receive_Session_Deleted_Lifecycle_Event_When_Deleted()
         await Client.DeleteSessionAsync(sessionId);
 
         var evt = await deleted.Task.WaitAsync(TimeSpan.FromSeconds(15));
-        Assert.Equal(SessionLifecycleEventTypes.Deleted, evt.Type);
+        Assert.IsType<SessionDeletedEvent>(evt);
         Assert.Equal(sessionId, evt.SessionId);
 
         await session.DisposeAsync();
diff --git a/dotnet/test/E2E/ClientOptionsE2ETests.cs b/dotnet/test/E2E/ClientOptionsE2ETests.cs
index af17205c0..142f46abb 100644
--- a/dotnet/test/E2E/ClientOptionsE2ETests.cs
+++ b/dotnet/test/E2E/ClientOptionsE2ETests.cs
@@ -1,4 +1,4 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
@@ -10,52 +10,20 @@
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class ClientOptionsE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "client_options", output)
 {
-    [Fact]
-    public async Task AutoStart_False_Requires_Explicit_Start()
-    {
-        await using var client = Ctx.CreateClient(options: new CopilotClientOptions
-        {
-            AutoStart = false,
-        });
-
-        Assert.Equal(ConnectionState.Disconnected, client.State);
-
-        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
-            client.CreateSessionAsync(new SessionConfig { OnPermissionRequest = PermissionHandler.ApproveAll }));
-        Assert.Contains("StartAsync", ex.Message, StringComparison.Ordinal);
-
-        await client.StartAsync();
-        Assert.Equal(ConnectionState.Connected, client.State);
-
-        var session = await client.CreateSessionAsync(new SessionConfig
-        {
-            OnPermissionRequest = PermissionHandler.ApproveAll,
-        });
-        Assert.Matches(@"^[a-f0-9-]+$", session.SessionId);
-
-        await session.DisposeAsync();
-    }
-
     [Fact]
     public async Task Should_Listen_On_Configured_Tcp_Port()
     {
         var port = GetAvailableTcpPort();
         await using var client = Ctx.CreateClient(
-            useStdio: false,
-            options: new CopilotClientOptions
-            {
-                Port = port,
-            });
+            options: new CopilotClientOptions { Connection = RuntimeConnection.ForTcp(port: port) });
 
         await client.StartAsync();
-
-        Assert.Equal(ConnectionState.Connected, client.State);
-        Assert.Equal(port, client.ActualPort);
+        Assert.Equal(port, client.RuntimePort);
 
         var response = await client.PingAsync("fixed-port");
         Assert.Equal("pong: fixed-port", response.Message);
@@ -70,7 +38,7 @@ public async Task Should_Use_Client_Cwd_For_Default_WorkingDirectory()
 
         await using var client = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            Cwd = clientCwd,
+            WorkingDirectory = clientCwd,
         });
 
         var session = await client.CreateSessionAsync(new SessionConfig
@@ -101,13 +69,11 @@ public async Task Should_Propagate_Process_Options_To_Spawned_Cli()
 
         await using var client = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            AutoStart = false,
-            CliPath = cliPath,
-            CliArgs = ["--capture-file", capturePath],
-            CopilotHome = copilotHomeFromOption,
+            Connection = RuntimeConnection.ForStdio(path: cliPath, args: ["--capture-file", capturePath]),
+            BaseDirectory = copilotHomeFromOption,
             Environment = clientEnv,
             GitHubToken = "process-option-token",
-            LogLevel = "debug",
+            LogLevel = CopilotLogLevel.Debug,
             SessionIdleTimeoutSeconds = 17,
             Telemetry = new TelemetryConfig
             {
@@ -165,9 +131,7 @@ public async Task Should_Forward_EnableSessionTelemetry_In_Wire_Request()
 
         await using var client = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            AutoStart = false,
-            CliPath = cliPath,
-            CliArgs = ["--capture-file", capturePath],
+            Connection = RuntimeConnection.ForStdio(path: cliPath, args: ["--capture-file", capturePath]),
             UseLoggedInUser = false,
         });
 
@@ -194,9 +158,7 @@ public async Task Should_Omit_EnableSessionTelemetry_When_Not_Set()
 
         await using var client = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            AutoStart = false,
-            CliPath = cliPath,
-            CliArgs = ["--capture-file", capturePath],
+            Connection = RuntimeConnection.ForStdio(path: cliPath, args: ["--capture-file", capturePath]),
             UseLoggedInUser = false,
         });
 
@@ -222,9 +184,7 @@ public async Task Should_Propagate_Activity_TraceContext_To_Session_Create_And_S
 
         await using var client = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            AutoStart = false,
-            CliPath = cliPath,
-            CliArgs = ["--capture-file", capturePath],
+            Connection = RuntimeConnection.ForStdio(path: cliPath, args: ["--capture-file", capturePath]),
             UseLoggedInUser = false,
         });
 
@@ -266,11 +226,9 @@ public async Task ForceStop_Does_Not_Rethrow_When_Tcp_Cli_Drops_During_Startup()
         await File.WriteAllTextAsync(cliPath, FakeTcpDropDuringStartupCliScript);
 
         await using var client = Ctx.CreateClient(
-            useStdio: false,
             options: new CopilotClientOptions
             {
-                AutoStart = false,
-                CliPath = cliPath,
+                Connection = RuntimeConnection.ForTcp(path: cliPath),
                 UseLoggedInUser = false,
             });
 
@@ -278,7 +236,6 @@ public async Task ForceStop_Does_Not_Rethrow_When_Tcp_Cli_Drops_During_Startup()
         Assert.Contains("Communication error", ex.Message, StringComparison.Ordinal);
 
         await client.ForceStopAsync();
-        Assert.Equal(ConnectionState.Disconnected, client.State);
     }
 
     [Fact]
@@ -290,12 +247,9 @@ public async Task StartAsync_Cleans_Up_Tcp_Cli_Process_When_Connect_Fails()
         await File.WriteAllTextAsync(cliPath, FakeTcpUnavailablePortCliScript);
 
         await using var client = Ctx.CreateClient(
-            useStdio: false,
             options: new CopilotClientOptions
             {
-                AutoStart = false,
-                CliPath = cliPath,
-                CliArgs = ["--pid-file", pidPath, "--announce-port", unavailablePort.ToString(CultureInfo.InvariantCulture)],
+                Connection = RuntimeConnection.ForTcp(path: cliPath, args: ["--pid-file", pidPath, "--announce-port", unavailablePort.ToString(CultureInfo.InvariantCulture)]),
                 UseLoggedInUser = false,
             });
 
@@ -305,7 +259,6 @@ public async Task StartAsync_Cleans_Up_Tcp_Cli_Process_When_Connect_Fails()
         await AssertProcessExitedAsync(pid);
 
         await client.ForceStopAsync();
-        Assert.Equal(ConnectionState.Disconnected, client.State);
     }
 
     [Fact]
@@ -315,9 +268,7 @@ public async Task Should_Propagate_Activity_TraceContext_To_Session_Resume()
 
         await using var client = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            AutoStart = false,
-            CliPath = cliPath,
-            CliArgs = ["--capture-file", capturePath],
+            Connection = RuntimeConnection.ForStdio(path: cliPath, args: ["--capture-file", capturePath]),
             UseLoggedInUser = false,
         });
 
@@ -385,28 +336,20 @@ public void Should_Allow_Explicit_UseLoggedInUser_True_With_GitHubToken()
     }
 
     [Fact]
-    public void Should_Throw_When_GitHubToken_Used_With_CliUrl()
+    public void Should_Throw_When_GitHubToken_Used_With_UriConnection()
     {
         Assert.Throws<ArgumentException>(() =>
         {
-            _ = new CopilotClient(new CopilotClientOptions
-            {
-                CliUrl = "localhost:8080",
-                GitHubToken = "gho_test_token"
-            });
+            _ = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri("localhost:8080"), GitHubToken = "gho_test_token" });
         });
     }
 
     [Fact]
-    public void Should_Throw_When_UseLoggedInUser_Used_With_CliUrl()
+    public void Should_Throw_When_UseLoggedInUser_Used_With_UriConnection()
     {
         Assert.Throws<ArgumentException>(() =>
         {
-            _ = new CopilotClient(new CopilotClientOptions
-            {
-                CliUrl = "localhost:8080",
-                UseLoggedInUser = false
-            });
+            _ = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri("localhost:8080"), UseLoggedInUser = false });
         });
     }
 
diff --git a/dotnet/test/E2E/ClientSessionManagementE2ETests.cs b/dotnet/test/E2E/ClientSessionManagementE2ETests.cs
index f2d54a1d5..961b0e028 100644
--- a/dotnet/test/E2E/ClientSessionManagementE2ETests.cs
+++ b/dotnet/test/E2E/ClientSessionManagementE2ETests.cs
@@ -5,7 +5,7 @@
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class ClientSessionManagementE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "client_api", output)
@@ -47,6 +47,14 @@ public async Task Should_Get_Null_Last_Session_Id_Before_Any_Sessions_Exist()
     {
         await Client.StartAsync();
 
+        // Other tests in this class create sessions, and xUnit doesn't guarantee
+        // test execution order. Clear any leftover sessions so this test sees a
+        // genuinely empty state regardless of order.
+        foreach (var existing in await Client.ListSessionsAsync())
+        {
+            await Client.DeleteSessionAsync(existing.SessionId);
+        }
+
         var result = await Client.GetLastSessionIdAsync();
 
         Assert.Null(result);
diff --git a/dotnet/test/E2E/CommandsE2ETests.cs b/dotnet/test/E2E/CommandsE2ETests.cs
index fd5e2165a..60a62bd58 100644
--- a/dotnet/test/E2E/CommandsE2ETests.cs
+++ b/dotnet/test/E2E/CommandsE2ETests.cs
@@ -5,7 +5,7 @@
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class CommandsE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "commands", output)
diff --git a/dotnet/test/E2E/CompactionE2ETests.cs b/dotnet/test/E2E/CompactionE2ETests.cs
index abee92219..63d467535 100644
--- a/dotnet/test/E2E/CompactionE2ETests.cs
+++ b/dotnet/test/E2E/CompactionE2ETests.cs
@@ -2,11 +2,11 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class CompactionE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "compaction", output)
 {
@@ -85,7 +85,7 @@ public async Task Should_Not_Emit_Compaction_Events_When_Infinite_Sessions_Disab
 
         var compactionEvents = new List<SessionEvent>();
 
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             if (evt is SessionCompactionStartEvent or SessionCompactionCompleteEvent)
             {
diff --git a/dotnet/test/E2E/ElicitationE2ETests.cs b/dotnet/test/E2E/ElicitationE2ETests.cs
index ca2714402..c14e11d55 100644
--- a/dotnet/test/E2E/ElicitationE2ETests.cs
+++ b/dotnet/test/E2E/ElicitationE2ETests.cs
@@ -1,12 +1,12 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
+using GitHub.Copilot.Rpc;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class ElicitationE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "elicitation", output)
@@ -56,7 +56,7 @@ public async Task Elicitation_Throws_When_Capability_Is_Missing()
 
         ex = await Assert.ThrowsAsync<InvalidOperationException>(async () =>
         {
-            await session.Ui.ElicitationAsync(new ElicitationParams
+            await session.Ui.ElicitAsync(new ElicitationParams
             {
                 Message = "Enter name",
                 RequestedSchema = new ElicitationSchema
@@ -199,7 +199,7 @@ public async Task InputAsync_Returns_Freeform_Value()
             },
         });
 
-        var result = await session.Ui.InputAsync("Enter value", new InputOptions
+        var result = await session.Ui.InputAsync("Enter value", new UiInputOptions
         {
             Title = "Value",
             Description = "A value to test",
@@ -246,9 +246,9 @@ public async Task ElicitationAsync_Returns_All_Action_Shapes()
             },
         };
 
-        var accept = await session.Ui.ElicitationAsync(parameters);
-        var decline = await session.Ui.ElicitationAsync(parameters);
-        var cancel = await session.Ui.ElicitationAsync(parameters);
+        var accept = await session.Ui.ElicitAsync(parameters);
+        var decline = await session.Ui.ElicitAsync(parameters);
+        var cancel = await session.Ui.ElicitAsync(parameters);
 
         Assert.Equal(UIElicitationResponseAction.Accept, accept.Action);
         Assert.Equal("Mona", accept.Content!["name"].ToString());
@@ -333,7 +333,7 @@ public void ElicitationResult_Types_Are_Properly_Structured()
     [Fact]
     public void InputOptions_Has_All_Properties()
     {
-        var options = new InputOptions
+        var options = new UiInputOptions
         {
             Title = "Email Address",
             Description = "Enter your email",
@@ -381,7 +381,7 @@ public void ElicitationContext_Has_All_Properties()
     [Fact]
     public async Task Session_Config_OnElicitationRequest_Is_Cloned()
     {
-        ElicitationHandler handler = _ => Task.FromResult(new ElicitationResult
+        Func<ElicitationContext, Task<ElicitationResult>> handler = _ => Task.FromResult(new ElicitationResult
         {
             Action = UIElicitationResponseAction.Cancel,
         });
@@ -400,7 +400,7 @@ public async Task Session_Config_OnElicitationRequest_Is_Cloned()
     [Fact]
     public void Resume_Config_OnElicitationRequest_Is_Cloned()
     {
-        ElicitationHandler handler = _ => Task.FromResult(new ElicitationResult
+        Func<ElicitationContext, Task<ElicitationResult>> handler = _ => Task.FromResult(new ElicitationResult
         {
             Action = UIElicitationResponseAction.Cancel,
         });
diff --git a/dotnet/test/E2E/ErrorResilienceE2ETests.cs b/dotnet/test/E2E/ErrorResilienceE2ETests.cs
index 4899f1386..ab69e8c43 100644
--- a/dotnet/test/E2E/ErrorResilienceE2ETests.cs
+++ b/dotnet/test/E2E/ErrorResilienceE2ETests.cs
@@ -1,11 +1,11 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Verifies the SDK's behavior at the edges of the session lifecycle: sending or
@@ -32,7 +32,7 @@ public async Task Should_Throw_When_Getting_Messages_From_Disconnected_Session()
         var session = await CreateSessionAsync();
         await session.DisposeAsync();
 
-        await Assert.ThrowsAnyAsync<Exception>(() => session.GetMessagesAsync());
+        await Assert.ThrowsAnyAsync<Exception>(() => session.GetEventsAsync());
     }
 
     [Fact]
diff --git a/dotnet/test/E2E/EventFidelityE2ETests.cs b/dotnet/test/E2E/EventFidelityE2ETests.cs
index fa034c565..4504984f9 100644
--- a/dotnet/test/E2E/EventFidelityE2ETests.cs
+++ b/dotnet/test/E2E/EventFidelityE2ETests.cs
@@ -1,12 +1,12 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Verifies the shape and ordering of <see cref="SessionEvent"/>s emitted from the
@@ -25,7 +25,7 @@ public async Task Should_Emit_Events_In_Correct_Order_For_Tool_Using_Conversatio
 
         var session = await CreateSessionAsync();
         var events = new List<SessionEvent>();
-        session.On(evt => { lock (events) { events.Add(evt); } });
+        session.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         await session.SendAndWaitAsync(new MessageOptions
         {
@@ -55,7 +55,7 @@ public async Task Should_Include_Valid_Fields_On_All_Events()
     {
         var session = await CreateSessionAsync();
         var events = new List<SessionEvent>();
-        session.On(evt => { lock (events) { events.Add(evt); } });
+        session.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         await session.SendAndWaitAsync(new MessageOptions
         {
@@ -91,7 +91,7 @@ public async Task Should_Emit_Assistant_Usage_Event_After_Model_Call()
     {
         var session = await CreateSessionAsync();
         var events = new List<SessionEvent>();
-        session.On(evt => { lock (events) { events.Add(evt); } });
+        session.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         await session.SendAndWaitAsync(new MessageOptions
         {
@@ -114,7 +114,7 @@ public async Task Should_Emit_Session_Usage_Info_Event_After_Model_Call()
     {
         var session = await CreateSessionAsync();
         var events = new List<SessionEvent>();
-        session.On(evt => { lock (events) { events.Add(evt); } });
+        session.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         await session.SendAndWaitAsync(new MessageOptions
         {
@@ -163,7 +163,7 @@ public async Task Should_Emit_Tool_Execution_Events_With_Correct_Fields()
 
         var session = await CreateSessionAsync();
         var events = new List<SessionEvent>();
-        session.On(evt => { lock (events) { events.Add(evt); } });
+        session.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         await session.SendAndWaitAsync(new MessageOptions
         {
@@ -194,7 +194,7 @@ public async Task Should_Emit_Assistant_Message_With_MessageId()
     {
         var session = await CreateSessionAsync();
         var events = new List<SessionEvent>();
-        session.On(evt => { lock (events) { events.Add(evt); } });
+        session.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         await session.SendAndWaitAsync(new MessageOptions
         {
@@ -225,7 +225,7 @@ await session.SendAndWaitAsync(new MessageOptions
             Prompt = "Read the file 'order.txt' and tell me what the number is.",
         });
 
-        var messages = await session.GetMessagesAsync();
+        var messages = await session.GetEventsAsync();
         var types = messages.Select(m => m.Type).ToList();
 
         // Verify complete event ordering contract:
diff --git a/dotnet/test/E2E/HookLifecycleAndOutputE2ETests.cs b/dotnet/test/E2E/HookLifecycleAndOutputE2ETests.cs
index 6bb589391..b16ee2b56 100644
--- a/dotnet/test/E2E/HookLifecycleAndOutputE2ETests.cs
+++ b/dotnet/test/E2E/HookLifecycleAndOutputE2ETests.cs
@@ -3,10 +3,11 @@
  *--------------------------------------------------------------------------------------------*/
 
 using Microsoft.Extensions.AI;
+using System.Text.Json;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// E2E coverage for every handler exposed on <see cref="SessionHooks"/>:
@@ -43,7 +44,7 @@ public async Task Should_Invoke_OnSessionStart_Hook_On_New_Session()
 
         Assert.NotEmpty(sessionStartInputs);
         Assert.Equal("new", sessionStartInputs[0].Source);
-        Assert.True(sessionStartInputs[0].Timestamp > 0);
+        Assert.True(sessionStartInputs[0].Timestamp > DateTimeOffset.UnixEpoch);
         Assert.False(string.IsNullOrEmpty(sessionStartInputs[0].Cwd));
 
         await session.DisposeAsync();
@@ -71,7 +72,7 @@ public async Task Should_Invoke_OnUserPromptSubmitted_Hook_When_Sending_A_Messag
 
         Assert.NotEmpty(userPromptInputs);
         Assert.Contains("Say hello", userPromptInputs[0].Prompt);
-        Assert.True(userPromptInputs[0].Timestamp > 0);
+        Assert.True(userPromptInputs[0].Timestamp > DateTimeOffset.UnixEpoch);
         Assert.False(string.IsNullOrEmpty(userPromptInputs[0].Cwd));
 
         await session.DisposeAsync();
@@ -116,7 +117,7 @@ public async Task Should_Invoke_OnErrorOccurred_Hook_When_Error_Occurs()
                 OnErrorOccurred = (input, invocation) =>
                 {
                     Assert.Equal(session!.SessionId, invocation.SessionId);
-                    Assert.True(input.Timestamp > 0);
+                    Assert.True(input.Timestamp > DateTimeOffset.UnixEpoch);
                     Assert.False(string.IsNullOrEmpty(input.Cwd));
                     Assert.False(string.IsNullOrEmpty(input.Error));
                     Assert.Contains(input.ErrorContext, ValidErrorContexts);
diff --git a/dotnet/test/E2E/HooksE2ETests.cs b/dotnet/test/E2E/HooksE2ETests.cs
index 28301bf25..ab971c26e 100644
--- a/dotnet/test/E2E/HooksE2ETests.cs
+++ b/dotnet/test/E2E/HooksE2ETests.cs
@@ -2,11 +2,11 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class HooksE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "hooks", output)
 {
diff --git a/dotnet/test/E2E/InMemorySessionFsSqliteHandler.cs b/dotnet/test/E2E/InMemorySessionFsSqliteHandler.cs
index 2bfc4b1d8..0ae9c9a7d 100644
--- a/dotnet/test/E2E/InMemorySessionFsSqliteHandler.cs
+++ b/dotnet/test/E2E/InMemorySessionFsSqliteHandler.cs
@@ -1,13 +1,13 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
 using System.Collections.Concurrent;
-using GitHub.Copilot.SDK;
-using GitHub.Copilot.SDK.Rpc;
+using GitHub.Copilot;
+using GitHub.Copilot.Rpc;
 using Microsoft.Data.Sqlite;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 internal record SqliteCall(string SessionId, string QueryType, string Query);
 
@@ -174,19 +174,19 @@ protected override Task<SessionFsStatResult> StatAsync(string path, Cancellation
         throw new FileNotFoundException($"Path does not exist: {path}");
     }
 
-    protected override Task MkdirAsync(string path, bool recursive, int? mode, CancellationToken cancellationToken)
+    protected override Task MakeDirectoryAsync(string path, bool recursive, int? mode, CancellationToken cancellationToken)
     {
         _directories[Resolve(path)] = 0;
         return Task.CompletedTask;
     }
 
-    protected override Task<IList<string>> ReaddirAsync(string path, CancellationToken cancellationToken)
+    protected override Task<IList<string>> ReadDirectoryAsync(string path, CancellationToken cancellationToken)
         => Task.FromResult<IList<string>>([]);
 
-    protected override Task<IList<SessionFsReaddirWithTypesEntry>> ReaddirWithTypesAsync(string path, CancellationToken cancellationToken)
+    protected override Task<IList<SessionFsReaddirWithTypesEntry>> ReadDirectoryWithTypesAsync(string path, CancellationToken cancellationToken)
         => Task.FromResult<IList<SessionFsReaddirWithTypesEntry>>([]);
 
-    protected override Task RmAsync(string path, bool recursive, bool force, CancellationToken cancellationToken)
+    protected override Task RemoveAsync(string path, bool recursive, bool force, CancellationToken cancellationToken)
     {
         var key = Resolve(path);
         Files.TryRemove(key, out _);
diff --git a/dotnet/test/E2E/ModeHandlersE2ETests.cs b/dotnet/test/E2E/ModeHandlersE2ETests.cs
index 0af54c4fd..061967a3b 100644
--- a/dotnet/test/E2E/ModeHandlersE2ETests.cs
+++ b/dotnet/test/E2E/ModeHandlersE2ETests.cs
@@ -1,12 +1,12 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class ModeHandlersE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "mode_handlers", output)
@@ -28,7 +28,7 @@ public async Task Should_Invoke_Exit_Plan_Mode_Handler_When_Model_Uses_Tool()
         {
             GitHubToken = Token,
             OnPermissionRequest = PermissionHandler.ApproveAll,
-            OnExitPlanMode = (request, invocation) =>
+            OnExitPlanModeRequest = (request, invocation) =>
             {
                 handlerTask.TrySetResult((request, invocation));
                 return Task.FromResult(new ExitPlanModeResult
@@ -96,7 +96,7 @@ public async Task Should_Invoke_Auto_Mode_Switch_Handler_When_Rate_Limited()
         {
             GitHubToken = Token,
             OnPermissionRequest = PermissionHandler.ApproveAll,
-            OnAutoModeSwitch = (request, invocation) =>
+            OnAutoModeSwitchRequest = (request, invocation) =>
             {
                 handlerTask.TrySetResult((request, invocation));
                 return Task.FromResult(AutoModeSwitchResponse.Yes);
@@ -176,7 +176,7 @@ private static async Task<T> GetNextEventOfTypeAllowingRateLimitAsync<T>(
         var tcs = new TaskCompletionSource<T>(TaskCreationOptions.RunContinuationsAsynchronously);
         using var cts = new CancellationTokenSource(timeout ?? TimeSpan.FromSeconds(30));
 
-        using var subscription = session.On(evt =>
+        using var subscription = session.On<SessionEvent>(evt =>
         {
             if (evt is T matched && predicate(matched))
             {
diff --git a/dotnet/test/E2E/MultiClientCommandsElicitationE2ETests.cs b/dotnet/test/E2E/MultiClientCommandsElicitationE2ETests.cs
index 5d70f51b1..d60c21709 100644
--- a/dotnet/test/E2E/MultiClientCommandsElicitationE2ETests.cs
+++ b/dotnet/test/E2E/MultiClientCommandsElicitationE2ETests.cs
@@ -1,12 +1,12 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Custom fixture for multi-client commands/elicitation tests.
@@ -22,9 +22,9 @@ public class MultiClientCommandsElicitationFixture : IAsyncLifetime
     public async Task InitializeAsync()
     {
         Ctx = await E2ETestContext.CreateAsync();
-        Client1 = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions
+        Client1 = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            TcpConnectionToken = SharedToken,
+            Connection = RuntimeConnection.ForTcp(connectionToken: SharedToken),
         }, persistent: true);
     }
 
@@ -65,13 +65,12 @@ public async Task InitializeAsync()
         });
         await initSession.DisposeAsync();
 
-        var port = Client1.ActualPort
-            ?? throw new InvalidOperationException("Client1 is not using TCP mode; ActualPort is null");
+        var port = Client1.RuntimePort
+            ?? throw new InvalidOperationException("Client1 is not using TCP mode; RuntimePort is null");
 
         _client2 = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            CliUrl = $"localhost:{port}",
-            TcpConnectionToken = MultiClientCommandsElicitationFixture.SharedToken,
+            Connection = RuntimeConnection.ForUri($"localhost:{port}", connectionToken: MultiClientCommandsElicitationFixture.SharedToken),
         });
     }
 
@@ -112,7 +111,7 @@ public async Task Client_Receives_Commands_Changed_When_Another_Client_Joins_Wit
         var commandsChangedTcs = new TaskCompletionSource<CommandsChangedEvent>(
             TaskCreationOptions.RunContinuationsAsynchronously);
 
-        using var sub = session1.On(evt =>
+        using var sub = session1.On<SessionEvent>(evt =>
         {
             if (evt is CommandsChangedEvent changed)
             {
@@ -133,7 +132,7 @@ public async Task Client_Receives_Commands_Changed_When_Another_Client_Joins_Wit
                     Handler = _ => Task.CompletedTask,
                 },
             ],
-            DisableResume = true,
+            SuppressResumeEvent = true,
         });
 
         var commandsChanged = await commandsChangedTcs.Task.WaitAsync(TimeSpan.FromSeconds(15));
@@ -160,7 +159,7 @@ public async Task Capabilities_Changed_Fires_When_Second_Client_Joins_With_Elici
         var capChangedTcs = new TaskCompletionSource<CapabilitiesChangedEvent>(
             TaskCreationOptions.RunContinuationsAsynchronously);
 
-        using var sub = session1.On(evt =>
+        using var sub = session1.On<SessionEvent>(evt =>
         {
             if (evt is CapabilitiesChangedEvent capEvt)
             {
@@ -177,7 +176,7 @@ public async Task Capabilities_Changed_Fires_When_Second_Client_Joins_With_Elici
                 Action = Rpc.UIElicitationResponseAction.Accept,
                 Content = new Dictionary<string, object>(),
             }),
-            DisableResume = true,
+            SuppressResumeEvent = true,
         });
 
         var capEvent = await capChangedTcs.Task.WaitAsync(TimeSpan.FromSeconds(15));
@@ -206,7 +205,7 @@ public async Task Capabilities_Changed_Fires_When_Elicitation_Provider_Disconnec
         var capEnabledTcs = new TaskCompletionSource<bool>(
             TaskCreationOptions.RunContinuationsAsynchronously);
 
-        using var subEnabled = session1.On(evt =>
+        using var subEnabled = session1.On<SessionEvent>(evt =>
         {
             if (evt is CapabilitiesChangedEvent { Data.Ui.Elicitation: true })
             {
@@ -215,12 +214,11 @@ public async Task Capabilities_Changed_Fires_When_Elicitation_Provider_Disconnec
         });
 
         // Use a dedicated client (client3) so we can stop it without affecting client2
-        var port = Client1.ActualPort
-            ?? throw new InvalidOperationException("Client1 ActualPort is null");
+        var port = Client1.RuntimePort
+            ?? throw new InvalidOperationException("Client1 RuntimePort is null");
         _client3 = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            CliUrl = $"localhost:{port}",
-            TcpConnectionToken = MultiClientCommandsElicitationFixture.SharedToken,
+            Connection = RuntimeConnection.ForUri($"localhost:{port}", connectionToken: MultiClientCommandsElicitationFixture.SharedToken),
         });
 
         // Client3 joins WITH elicitation handler
@@ -232,7 +230,7 @@ public async Task Capabilities_Changed_Fires_When_Elicitation_Provider_Disconnec
                 Action = Rpc.UIElicitationResponseAction.Accept,
                 Content = new Dictionary<string, object>(),
             }),
-            DisableResume = true,
+            SuppressResumeEvent = true,
         });
 
         await capEnabledTcs.Task.WaitAsync(TimeSpan.FromSeconds(15));
@@ -242,7 +240,7 @@ public async Task Capabilities_Changed_Fires_When_Elicitation_Provider_Disconnec
         var capDisabledTcs = new TaskCompletionSource<bool>(
             TaskCreationOptions.RunContinuationsAsynchronously);
 
-        using var subDisabled = session1.On(evt =>
+        using var subDisabled = session1.On<SessionEvent>(evt =>
         {
             if (evt is CapabilitiesChangedEvent { Data.Ui.Elicitation: false })
             {
diff --git a/dotnet/test/E2E/MultiClientE2ETests.cs b/dotnet/test/E2E/MultiClientE2ETests.cs
index bd939a6cf..34efd09b2 100644
--- a/dotnet/test/E2E/MultiClientE2ETests.cs
+++ b/dotnet/test/E2E/MultiClientE2ETests.cs
@@ -2,14 +2,14 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Microsoft.Extensions.AI;
 using System.Collections.Concurrent;
 using System.ComponentModel;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Custom fixture for multi-client tests that uses TCP mode so a second client can connect.
@@ -24,9 +24,9 @@ public class MultiClientTestFixture : IAsyncLifetime
     public async Task InitializeAsync()
     {
         Ctx = await E2ETestContext.CreateAsync();
-        Client1 = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions
+        Client1 = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            TcpConnectionToken = SharedToken,
+            Connection = RuntimeConnection.ForTcp(connectionToken: SharedToken),
         }, persistent: true);
     }
 
@@ -63,13 +63,12 @@ public async Task InitializeAsync()
         });
         await initSession.DisposeAsync();
 
-        var port = Client1.ActualPort
-            ?? throw new InvalidOperationException("Client1 is not using TCP mode; ActualPort is null");
+        var port = Client1.RuntimePort
+            ?? throw new InvalidOperationException("Client1 is not using TCP mode; RuntimePort is null");
 
         _client2 = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            CliUrl = $"localhost:{port}",
-            TcpConnectionToken = MultiClientTestFixture.SharedToken,
+            Connection = RuntimeConnection.ForUri($"localhost:{port}", connectionToken: MultiClientTestFixture.SharedToken),
         });
     }
 
@@ -113,12 +112,12 @@ public async Task Both_Clients_See_Tool_Request_And_Completion_Events()
         var client1Completed = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
         var client2Completed = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
 
-        using var sub1 = session1.On(evt =>
+        using var sub1 = session1.On<SessionEvent>(evt =>
         {
             if (evt is ExternalToolRequestedEvent) client1Requested.TrySetResult(true);
             if (evt is ExternalToolCompletedEvent) client1Completed.TrySetResult(true);
         });
-        using var sub2 = session2.On(evt =>
+        using var sub2 = session2.On<SessionEvent>(evt =>
         {
             if (evt is ExternalToolRequestedEvent) client2Requested.TrySetResult(true);
             if (evt is ExternalToolCompletedEvent) client2Completed.TrySetResult(true);
@@ -173,8 +172,8 @@ public async Task One_Client_Approves_Permission_And_Both_See_The_Result()
         var client1PermissionCompleted = TestHelper.GetNextEventOfTypeAsync<PermissionCompletedEvent>(session1);
         var client2PermissionCompleted = TestHelper.GetNextEventOfTypeAsync<PermissionCompletedEvent>(session2);
 
-        using var sub1 = session1.On(evt => client1Events.Add(evt));
-        using var sub2 = session2.On(evt => client2Events.Add(evt));
+        using var sub1 = session1.On<SessionEvent>(evt => client1Events.Add(evt));
+        using var sub2 = session2.On<SessionEvent>(evt => client2Events.Add(evt));
 
         await session1.SendAsync(new MessageOptions
         {
@@ -223,8 +222,8 @@ public async Task One_Client_Rejects_Permission_And_Both_See_The_Result()
         // Wait for PermissionCompletedEvent on client2 which may arrive slightly after session1 goes idle
         var client2PermissionCompleted = TestHelper.GetNextEventOfTypeAsync<PermissionCompletedEvent>(session2);
 
-        using var sub1 = session1.On(evt => client1Events.Add(evt));
-        using var sub2 = session2.On(evt => client2Events.Add(evt));
+        using var sub1 = session1.On<SessionEvent>(evt => client1Events.Add(evt));
+        using var sub2 = session2.On<SessionEvent>(evt => client2Events.Add(evt));
 
         // Write a file so the agent has something to edit
         await File.WriteAllTextAsync(Path.Combine(Ctx.WorkDir, "protected.txt"), "protected content");
@@ -331,11 +330,10 @@ public async Task Disconnecting_Client_Removes_Its_Tools()
         await Client2.ForceStopAsync();
 
         // Recreate client2 for cleanup
-        var port = Client1.ActualPort!.Value;
+        var port = Client1.RuntimePort!.Value;
         _client2 = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            CliUrl = $"localhost:{port}",
-            TcpConnectionToken = MultiClientTestFixture.SharedToken,
+            Connection = RuntimeConnection.ForUri($"localhost:{port}", connectionToken: MultiClientTestFixture.SharedToken),
         });
 
         // Now only stable_tool should be available
diff --git a/dotnet/test/E2E/MultiTurnE2ETests.cs b/dotnet/test/E2E/MultiTurnE2ETests.cs
index b10acfbc2..4cfff92d4 100644
--- a/dotnet/test/E2E/MultiTurnE2ETests.cs
+++ b/dotnet/test/E2E/MultiTurnE2ETests.cs
@@ -5,7 +5,7 @@
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Verifies that information produced in one turn (e.g., the contents of a file
@@ -23,7 +23,7 @@ public async Task Should_Use_Tool_Results_From_Previous_Turns()
         var session = await CreateSessionAsync();
         var events = new List<SessionEvent>();
         var eventsLock = new object();
-        using var subscription = session.On(evt =>
+        using var subscription = session.On<SessionEvent>(evt =>
         {
             lock (eventsLock)
             {
@@ -52,7 +52,7 @@ public async Task Should_Handle_File_Creation_Then_Reading_Across_Turns()
         var session = await CreateSessionAsync();
         var events = new List<SessionEvent>();
         var eventsLock = new object();
-        using var subscription = session.On(evt =>
+        using var subscription = session.On<SessionEvent>(evt =>
         {
             lock (eventsLock)
             {
diff --git a/dotnet/test/E2E/PendingWorkResumeE2ETests.cs b/dotnet/test/E2E/PendingWorkResumeE2ETests.cs
index f78ba0d70..889dc0050 100644
--- a/dotnet/test/E2E/PendingWorkResumeE2ETests.cs
+++ b/dotnet/test/E2E/PendingWorkResumeE2ETests.cs
@@ -1,15 +1,15 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Microsoft.Extensions.AI;
 using System.ComponentModel;
 using Xunit;
 using Xunit.Abstractions;
-using RpcPermissionDecisionApproveOnce = GitHub.Copilot.SDK.Rpc.PermissionDecisionApproveOnce;
+using RpcPermissionDecisionApproveOnce = GitHub.Copilot.Rpc.PermissionDecisionApproveOnce;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class PendingWorkResumeE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "pending_work_resume", output)
@@ -24,11 +24,11 @@ public async Task Should_Continue_Pending_Permission_Request_After_Resume()
         var releaseOriginalPermission = new TaskCompletionSource<PermissionRequestResult>(TaskCreationOptions.RunContinuationsAsynchronously);
         var resumedToolInvoked = false;
 
-        await using var server = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions { TcpConnectionToken = SharedToken });
+        await using var server = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForTcp(connectionToken: SharedToken) });
         await server.StartAsync();
         var cliUrl = GetCliUrl(server);
 
-        using var suspendedClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken });
+        using var suspendedClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) });
         var session1 = await suspendedClient.CreateSessionAsync(new SessionConfig
         {
             Tools = [AIFunctionFactory.Create(ResumePermissionTool, "resume_permission_tool")],
@@ -55,7 +55,7 @@ await session1.SendAsync(new MessageOptions
 
             await suspendedClient.ForceStopAsync();
 
-            await using var resumedTcpClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken });
+            await using var resumedTcpClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) });
             var session2 = await resumedTcpClient.ResumeSessionAsync(sessionId, new ResumeSessionConfig
             {
                 ContinuePendingWork = true,
@@ -107,11 +107,11 @@ public async Task Should_Continue_Pending_External_Tool_Request_After_Resume()
         var originalToolStarted = new TaskCompletionSource<string>(TaskCreationOptions.RunContinuationsAsynchronously);
         var releaseOriginalTool = new TaskCompletionSource<string>(TaskCreationOptions.RunContinuationsAsynchronously);
 
-        await using var server = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions { TcpConnectionToken = SharedToken });
+        await using var server = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForTcp(connectionToken: SharedToken) });
         await server.StartAsync();
         var cliUrl = GetCliUrl(server);
 
-        using var suspendedClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken });
+        using var suspendedClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) });
         var session1 = await suspendedClient.CreateSessionAsync(new SessionConfig
         {
             Tools = [AIFunctionFactory.Create(BlockingExternalTool, "resume_external_tool")],
@@ -132,7 +132,7 @@ await session1.SendAsync(new MessageOptions
             Assert.Equal("beta", await originalToolStarted.Task.WaitAsync(PendingWorkTimeout));
             await suspendedClient.ForceStopAsync();
 
-            await using var resumedClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken });
+            await using var resumedClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) });
             var session2 = await resumedClient.ResumeSessionAsync(sessionId, new ResumeSessionConfig
             {
                 ContinuePendingWork = true,
@@ -171,11 +171,11 @@ public async Task Should_Keep_Pending_External_Tool_Handleable_On_Warm_Resume_Wh
         var releaseOriginalTool = new TaskCompletionSource<string>(TaskCreationOptions.RunContinuationsAsynchronously);
         var invocationCount = 0;
 
-        await using var server = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions { TcpConnectionToken = SharedToken });
+        await using var server = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForTcp(connectionToken: SharedToken) });
         await server.StartAsync();
         var cliUrl = GetCliUrl(server);
 
-        using var suspendedClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken });
+        using var suspendedClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) });
         var session1 = await suspendedClient.CreateSessionAsync(new SessionConfig
         {
             Tools = [AIFunctionFactory.Create(BlockingExternalTool, "resume_external_tool")],
@@ -197,7 +197,7 @@ await session1.SendAsync(new MessageOptions
 
             await suspendedClient.ForceStopAsync();
 
-            await using var resumedClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken });
+            await using var resumedClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) });
             var session2 = await resumedClient.ResumeSessionAsync(sessionId, new ResumeSessionConfig
             {
                 ContinuePendingWork = false,
@@ -242,11 +242,11 @@ public async Task Should_Continue_Parallel_Pending_External_Tool_Requests_After_
         var releaseOriginalToolA = new TaskCompletionSource<string>(TaskCreationOptions.RunContinuationsAsynchronously);
         var releaseOriginalToolB = new TaskCompletionSource<string>(TaskCreationOptions.RunContinuationsAsynchronously);
 
-        await using var server = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions { TcpConnectionToken = SharedToken });
+        await using var server = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForTcp(connectionToken: SharedToken) });
         await server.StartAsync();
         var cliUrl = GetCliUrl(server);
 
-        using var suspendedClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken });
+        using var suspendedClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) });
         var session1 = await suspendedClient.CreateSessionAsync(new SessionConfig
         {
             Tools =
@@ -276,7 +276,7 @@ await Task.WhenAll(
 
             await suspendedClient.ForceStopAsync();
 
-            await using var resumedClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken });
+            await using var resumedClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) });
             var session2 = await resumedClient.ResumeSessionAsync(sessionId, new ResumeSessionConfig
             {
                 ContinuePendingWork = true,
@@ -321,12 +321,12 @@ async Task<string> BlockingToolB([Description("Value to look up")] string value)
     [Fact]
     public async Task Should_Resume_Successfully_When_No_Pending_Work_Exists()
     {
-        await using var server = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions { TcpConnectionToken = SharedToken });
+        await using var server = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForTcp(connectionToken: SharedToken) });
         await server.StartAsync();
         var cliUrl = GetCliUrl(server);
 
         string sessionId;
-        await using (var firstClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken }))
+        await using (var firstClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) }))
         {
             var firstSession = await firstClient.CreateSessionAsync(new SessionConfig
             {
@@ -340,7 +340,7 @@ public async Task Should_Resume_Successfully_When_No_Pending_Work_Exists()
             await firstSession.DisposeAsync();
         }
 
-        await using var resumedClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken });
+        await using var resumedClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) });
         var resumedSession = await resumedClient.ResumeSessionAsync(sessionId, new ResumeSessionConfig
         {
             ContinuePendingWork = true,
@@ -359,12 +359,12 @@ public async Task Should_Resume_Successfully_When_No_Pending_Work_Exists()
     [Fact]
     public async Task Should_Report_ContinuePendingWork_True_In_Resume_Event()
     {
-        await using var server = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions { TcpConnectionToken = SharedToken });
+        await using var server = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForTcp(connectionToken: SharedToken) });
         await server.StartAsync();
         var cliUrl = GetCliUrl(server);
 
         string sessionId;
-        await using (var firstClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken }))
+        await using (var firstClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) }))
         {
             var firstSession = await firstClient.CreateSessionAsync(new SessionConfig
             {
@@ -381,7 +381,7 @@ public async Task Should_Report_ContinuePendingWork_True_In_Resume_Event()
             await firstSession.DisposeAsync();
         }
 
-        await using var resumedClient = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = SharedToken });
+        await using var resumedClient = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: SharedToken) });
         var resumedSession = await resumedClient.ResumeSessionAsync(sessionId, new ResumeSessionConfig
         {
             ContinuePendingWork = true,
@@ -420,7 +420,7 @@ private static async Task<Dictionary<string, ExternalToolRequestedEvent>> WaitFo
             TaskCreationOptions.RunContinuationsAsynchronously);
         using var cts = new CancellationTokenSource(PendingWorkTimeout);
 
-        using var subscription = session.On(evt =>
+        using var subscription = session.On<SessionEvent>(evt =>
         {
             if (evt is ExternalToolRequestedEvent toolEvent && expected.Contains(toolEvent.Data.ToolName))
             {
@@ -444,14 +444,14 @@ private static async Task<Dictionary<string, ExternalToolRequestedEvent>> WaitFo
 
     private static string GetCliUrl(CopilotClient client)
     {
-        var port = client.ActualPort
+        var port = client.RuntimePort
             ?? throw new InvalidOperationException("Expected the test server to be listening on a TCP port.");
         return $"localhost:{port}";
     }
 
     private static async Task<SessionResumeEvent> GetSingleResumeEventAsync(CopilotSession session)
     {
-        var messages = await session.GetMessagesAsync();
+        var messages = await session.GetEventsAsync();
         return Assert.Single(messages.OfType<SessionResumeEvent>());
     }
 }
diff --git a/dotnet/test/E2E/PerSessionAuthE2ETests.cs b/dotnet/test/E2E/PerSessionAuthE2ETests.cs
index f93da300c..42a433f9d 100644
--- a/dotnet/test/E2E/PerSessionAuthE2ETests.cs
+++ b/dotnet/test/E2E/PerSessionAuthE2ETests.cs
@@ -2,11 +2,11 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class PerSessionAuthE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "per-session-auth", output)
 {
diff --git a/dotnet/test/E2E/PermissionE2ETests.cs b/dotnet/test/E2E/PermissionE2ETests.cs
index 9dd7a549f..953ab1469 100644
--- a/dotnet/test/E2E/PermissionE2ETests.cs
+++ b/dotnet/test/E2E/PermissionE2ETests.cs
@@ -2,14 +2,14 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Microsoft.Extensions.AI;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public partial class PermissionE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "permissions", output)
 {
@@ -100,7 +100,7 @@ public async Task Should_Deny_Permission_When_Handler_Returns_Denied()
         // for the reject decision, which lets us assert the decision was honored
         // — not merely that the operation didn't happen.
         var userRejectedToolCall = false;
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             if (evt is ToolExecutionCompleteEvent toolEvt &&
                 !toolEvt.Data.Success &&
@@ -139,7 +139,7 @@ public async Task Should_Deny_Tool_Operations_When_Handler_Explicitly_Denies()
         });
         var permissionDenied = false;
 
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             if (evt is ToolExecutionCompleteEvent toolEvt &&
                 !toolEvt.Data.Success &&
@@ -266,7 +266,7 @@ public async Task Should_Deny_Tool_Operations_When_Handler_Explicitly_Denies_Aft
         });
         var permissionDenied = false;
 
-        session2.On(evt =>
+        session2.On<SessionEvent>(evt =>
         {
             if (evt is ToolExecutionCompleteEvent toolEvt &&
                 !toolEvt.Data.Success &&
@@ -344,7 +344,7 @@ void AddLifecycleEvent(string phase, string? toolCallId)
             }
         });
 
-        using var subscription = session.On(evt =>
+        using var subscription = session.On<SessionEvent>(evt =>
         {
             switch (evt)
             {
@@ -442,7 +442,7 @@ public async Task Should_Handle_Concurrent_Permission_Requests_From_Parallel_Too
             }
         });
 
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             if (evt is ToolExecutionCompleteEvent toolEvt)
             {
@@ -554,7 +554,7 @@ public async Task Should_Short_Circuit_Permission_Handler_When_Set_Approve_All_E
         try
         {
             var toolCompleted = new TaskCompletionSource<ToolExecutionCompleteEvent>(TaskCreationOptions.RunContinuationsAsynchronously);
-            using var subscription = session.On(evt =>
+            using var subscription = session.On<SessionEvent>(evt =>
             {
                 if (evt is ToolExecutionCompleteEvent done && done.Data.Success)
                 {
diff --git a/dotnet/test/E2E/RpcAdditionalEdgeCasesE2ETests.cs b/dotnet/test/E2E/RpcAdditionalEdgeCasesE2ETests.cs
index 238299c02..241a978a9 100644
--- a/dotnet/test/E2E/RpcAdditionalEdgeCasesE2ETests.cs
+++ b/dotnet/test/E2E/RpcAdditionalEdgeCasesE2ETests.cs
@@ -2,12 +2,12 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Targeted gap-filler tests for assorted RPC surface area where the previous suite covered
diff --git a/dotnet/test/E2E/RpcAgentE2ETests.cs b/dotnet/test/E2E/RpcAgentE2ETests.cs
index b64e858e4..cd60a2934 100644
--- a/dotnet/test/E2E/RpcAgentE2ETests.cs
+++ b/dotnet/test/E2E/RpcAgentE2ETests.cs
@@ -2,12 +2,12 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class RpcAgentE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "rpc_agents", output)
diff --git a/dotnet/test/E2E/RpcEventSideEffectsE2ETests.cs b/dotnet/test/E2E/RpcEventSideEffectsE2ETests.cs
index a363b5586..9622553d1 100644
--- a/dotnet/test/E2E/RpcEventSideEffectsE2ETests.cs
+++ b/dotnet/test/E2E/RpcEventSideEffectsE2ETests.cs
@@ -1,13 +1,13 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Verifies that session-scoped RPC calls emit the expected side-effect session events.
@@ -140,7 +140,7 @@ public async Task Should_Emit_Snapshot_Rewind_Event_And_Remove_Events_On_Truncat
         // gates flushing on shouldSaveSession, which flips on the first user.message).
         await session.SendAndWaitAsync(new MessageOptions { Prompt = "Say SNAPSHOT_REWIND_TARGET exactly." });
 
-        var messages = await session.GetMessagesAsync();
+        var messages = await session.GetEventsAsync();
         var userEvent = messages.OfType<UserMessageEvent>().FirstOrDefault()
             ?? throw new InvalidOperationException("Expected at least one user.message in persisted history");
         var targetEventId = userEvent.Id.ToString();
@@ -161,7 +161,7 @@ public async Task Should_Emit_Snapshot_Rewind_Event_And_Remove_Events_On_Truncat
         Assert.Equal(truncateResult.EventsRemoved, (long)rewindEvent.Data.EventsRemoved);
 
         // Verify the truncated event is no longer in persisted history.
-        var messagesAfter = await session.GetMessagesAsync();
+        var messagesAfter = await session.GetEventsAsync();
         Assert.DoesNotContain(messagesAfter, e => e.Id == userEvent.Id);
     }
 
@@ -172,7 +172,7 @@ public async Task Should_Allow_Session_Use_After_Truncate()
 
         await session.SendAndWaitAsync(new MessageOptions { Prompt = "Say SNAPSHOT_REWIND_TARGET exactly." });
 
-        var messages = await session.GetMessagesAsync();
+        var messages = await session.GetEventsAsync();
         var userEvent = messages.OfType<UserMessageEvent>().FirstOrDefault()
             ?? throw new InvalidOperationException("Expected at least one user.message in persisted history");
 
diff --git a/dotnet/test/E2E/RpcExtensionsLoadedE2ETests.cs b/dotnet/test/E2E/RpcExtensionsLoadedE2ETests.cs
index 4d4388b22..1219b14a4 100644
--- a/dotnet/test/E2E/RpcExtensionsLoadedE2ETests.cs
+++ b/dotnet/test/E2E/RpcExtensionsLoadedE2ETests.cs
@@ -2,14 +2,14 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using System.Diagnostics;
 using Xunit;
 using Xunit.Abstractions;
-using RpcExtension = GitHub.Copilot.SDK.Rpc.Extension;
+using RpcExtension = GitHub.Copilot.Rpc.Extension;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// E2E coverage for the loaded-extensions code path in the runtime: when the
@@ -57,7 +57,7 @@ private CopilotClient CreateExtensionsClient()
     {
         return Ctx.CreateClient(options: new CopilotClientOptions
         {
-            CliArgs = ["--yolo"],
+            Connection = RuntimeConnection.ForStdio(args: ["--yolo"]),
             Environment = ExtensionsEnabledEnvironment(),
         });
     }
diff --git a/dotnet/test/E2E/RpcMcpAndSkillsE2ETests.cs b/dotnet/test/E2E/RpcMcpAndSkillsE2ETests.cs
index 03cab27de..a3d08a1cb 100644
--- a/dotnet/test/E2E/RpcMcpAndSkillsE2ETests.cs
+++ b/dotnet/test/E2E/RpcMcpAndSkillsE2ETests.cs
@@ -4,10 +4,10 @@
 
 using Xunit;
 using Xunit.Abstractions;
-using RpcSkill = GitHub.Copilot.SDK.Rpc.Skill;
-using RpcSkillList = GitHub.Copilot.SDK.Rpc.SkillList;
+using RpcSkill = GitHub.Copilot.Rpc.Skill;
+using RpcSkillList = GitHub.Copilot.Rpc.SkillList;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class RpcMcpAndSkillsE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "rpc_mcp_and_skills", output)
@@ -102,7 +102,7 @@ public async Task Should_List_Extensions()
         // preventing breakage from new gates (e.g., extension-permission-access).
         await using var yoloClient = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            CliArgs = ["--yolo"],
+            Connection = RuntimeConnection.ForStdio(args: ["--yolo"]),
         });
         await using var session = await yoloClient.CreateSessionAsync(new SessionConfig
         {
@@ -188,7 +188,7 @@ public async Task Should_Report_Error_When_Extensions_Are_Not_Available()
         // preventing breakage from new gates (e.g., extension-permission-access).
         await using var yoloClient = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            CliArgs = ["--yolo"],
+            Connection = RuntimeConnection.ForStdio(args: ["--yolo"]),
         });
         await using var session = await yoloClient.CreateSessionAsync(new SessionConfig
         {
diff --git a/dotnet/test/E2E/RpcMcpConfigE2ETests.cs b/dotnet/test/E2E/RpcMcpConfigE2ETests.cs
index 179fc4828..d26e5535d 100644
--- a/dotnet/test/E2E/RpcMcpConfigE2ETests.cs
+++ b/dotnet/test/E2E/RpcMcpConfigE2ETests.cs
@@ -2,12 +2,12 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
+using GitHub.Copilot.Rpc;
 using System.Text.Json;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class RpcMcpConfigE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "rpc_mcp_config", output)
diff --git a/dotnet/test/E2E/RpcServerE2ETests.cs b/dotnet/test/E2E/RpcServerE2ETests.cs
index b7d7e4624..39913060c 100644
--- a/dotnet/test/E2E/RpcServerE2ETests.cs
+++ b/dotnet/test/E2E/RpcServerE2ETests.cs
@@ -2,11 +2,11 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class RpcServerE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "rpc_server", output)
diff --git a/dotnet/test/E2E/RpcSessionStateE2ETests.cs b/dotnet/test/E2E/RpcSessionStateE2ETests.cs
index ff0e9bd8f..04ba27f54 100644
--- a/dotnet/test/E2E/RpcSessionStateE2ETests.cs
+++ b/dotnet/test/E2E/RpcSessionStateE2ETests.cs
@@ -1,13 +1,13 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class RpcSessionStateE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "rpc_session_state", output)
@@ -252,7 +252,7 @@ public async Task Should_Fork_Session_With_Persisted_Messages()
         var initialAnswer = await session.SendAndWaitAsync(new MessageOptions { Prompt = sourcePrompt });
         Assert.Contains("FORK_SOURCE_ALPHA", initialAnswer?.Data.Content ?? string.Empty);
 
-        var sourceConversation = GetConversationMessages(await session.GetMessagesAsync());
+        var sourceConversation = GetConversationMessages(await session.GetEventsAsync());
         Assert.Contains(sourceConversation, message => message.Role == "user" && message.Content == sourcePrompt);
         Assert.Contains(sourceConversation, message => message.Role == "assistant" && message.Content.Contains("FORK_SOURCE_ALPHA", StringComparison.Ordinal));
 
@@ -261,16 +261,16 @@ public async Task Should_Fork_Session_With_Persisted_Messages()
         Assert.NotEqual(session.SessionId, fork.SessionId);
 
         await using var forkedSession = await ResumeSessionAsync(fork.SessionId);
-        var forkedConversation = GetConversationMessages(await forkedSession.GetMessagesAsync());
+        var forkedConversation = GetConversationMessages(await forkedSession.GetEventsAsync());
         Assert.Equal(sourceConversation, forkedConversation.Take(sourceConversation.Count));
 
         var forkAnswer = await forkedSession.SendAndWaitAsync(new MessageOptions { Prompt = forkPrompt });
         Assert.Contains("FORK_CHILD_BETA", forkAnswer?.Data.Content ?? string.Empty);
 
-        var sourceAfterFork = GetConversationMessages(await session.GetMessagesAsync());
+        var sourceAfterFork = GetConversationMessages(await session.GetEventsAsync());
         Assert.DoesNotContain(sourceAfterFork, message => message.Content == forkPrompt);
 
-        var forkAfterPrompt = GetConversationMessages(await forkedSession.GetMessagesAsync());
+        var forkAfterPrompt = GetConversationMessages(await forkedSession.GetEventsAsync());
         Assert.Contains(forkAfterPrompt, message => message.Role == "user" && message.Content == forkPrompt);
         Assert.Contains(forkAfterPrompt, message => message.Role == "assistant" && message.Content.Contains("FORK_CHILD_BETA", StringComparison.Ordinal));
     }
@@ -298,7 +298,7 @@ public async Task Should_Handle_Forking_Session_Without_Persisted_Events()
         Assert.NotEqual(session.SessionId, forkSessionId);
 
         await using var forkedSession = await ResumeSessionAsync(forkSessionId);
-        Assert.Empty(GetConversationMessages(await forkedSession.GetMessagesAsync()));
+        Assert.Empty(GetConversationMessages(await forkedSession.GetEventsAsync()));
     }
 
     [Fact]
@@ -311,7 +311,7 @@ public async Task Should_Fork_Session_To_Event_Id_Excluding_Boundary_Event()
         await session.SendAndWaitAsync(new MessageOptions { Prompt = firstPrompt });
         await session.SendAndWaitAsync(new MessageOptions { Prompt = secondPrompt });
 
-        var sourceEvents = await session.GetMessagesAsync();
+        var sourceEvents = await session.GetEventsAsync();
         var secondUserEvent = sourceEvents
             .OfType<UserMessageEvent>()
             .FirstOrDefault(e => string.Equals(e.Data.Content, secondPrompt, StringComparison.Ordinal))
@@ -325,7 +325,7 @@ public async Task Should_Fork_Session_To_Event_Id_Excluding_Boundary_Event()
         Assert.NotEqual(session.SessionId, fork.SessionId);
 
         await using var forkedSession = await ResumeSessionAsync(fork.SessionId);
-        var forkedEvents = await forkedSession.GetMessagesAsync();
+        var forkedEvents = await forkedSession.GetEventsAsync();
         Assert.DoesNotContain(forkedEvents, e => e.Id == secondUserEvent.Id);
 
         var forkedConversation = GetConversationMessages(forkedEvents);
diff --git a/dotnet/test/E2E/RpcShellAndFleetE2ETests.cs b/dotnet/test/E2E/RpcShellAndFleetE2ETests.cs
index ee9ebb27d..a51fc7dae 100644
--- a/dotnet/test/E2E/RpcShellAndFleetE2ETests.cs
+++ b/dotnet/test/E2E/RpcShellAndFleetE2ETests.cs
@@ -1,13 +1,13 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Microsoft.Extensions.AI;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class RpcShellAndFleetE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "rpc_shell_and_fleet", output)
@@ -118,7 +118,7 @@ private static async Task<IReadOnlyList<SessionEvent>> WaitForMessagesAsync(
         await TestHelper.WaitForConditionAsync(
             async () =>
             {
-                messages = (await session.GetMessagesAsync()).ToList();
+                messages = (await session.GetEventsAsync()).ToList();
                 return predicate(messages);
             },
             timeout: TimeSpan.FromSeconds(120),
diff --git a/dotnet/test/E2E/RpcShellEdgeCaseE2ETests.cs b/dotnet/test/E2E/RpcShellEdgeCaseE2ETests.cs
index 6b7a9c5e0..b6036b7b8 100644
--- a/dotnet/test/E2E/RpcShellEdgeCaseE2ETests.cs
+++ b/dotnet/test/E2E/RpcShellEdgeCaseE2ETests.cs
@@ -2,12 +2,12 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Targeted edge-case tests for the shell RPC API (<c>shell.exec</c>, <c>shell.kill</c>).
diff --git a/dotnet/test/E2E/RpcTasksAndHandlersE2ETests.cs b/dotnet/test/E2E/RpcTasksAndHandlersE2ETests.cs
index 6e8860964..2ed338129 100644
--- a/dotnet/test/E2E/RpcTasksAndHandlersE2ETests.cs
+++ b/dotnet/test/E2E/RpcTasksAndHandlersE2ETests.cs
@@ -2,12 +2,12 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class RpcTasksAndHandlersE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "rpc_tasks_and_handlers", output)
@@ -101,7 +101,7 @@ await TestHelper.WaitForConditionAsync(
         Assert.Equal("general-purpose", task.AgentType);
         Assert.Equal("Reply with TASK_AGENT_DONE exactly.", task.Prompt);
         Assert.Equal("SDK background agent coverage", task.Description);
-        Assert.Equal(GitHub.Copilot.SDK.Rpc.TaskExecutionMode.Background, task.ExecutionMode);
+        Assert.Equal(GitHub.Copilot.Rpc.TaskExecutionMode.Background, task.ExecutionMode);
         Assert.False(task.CanPromoteToBackground.GetValueOrDefault());
         Assert.NotEqual(default, task.StartedAt);
 
@@ -114,8 +114,8 @@ await TestHelper.WaitForConditionAsync(
                 task = await FindAgentTaskAsync(session, started.AgentId);
                 return task?.LatestResponse?.Contains("TASK_AGENT_DONE", StringComparison.Ordinal) == true
                     || task?.Result?.Contains("TASK_AGENT_DONE", StringComparison.Ordinal) == true
-                    || task?.Status == GitHub.Copilot.SDK.Rpc.TaskStatus.Completed
-                    || task?.Status == GitHub.Copilot.SDK.Rpc.TaskStatus.Failed;
+                    || task?.Status == GitHub.Copilot.Rpc.TaskStatus.Completed
+                    || task?.Status == GitHub.Copilot.Rpc.TaskStatus.Failed;
             },
             timeout: TimeSpan.FromSeconds(60),
             timeoutMessage: $"Background agent task '{started.AgentId}' did not produce a final observable state.");
@@ -123,7 +123,7 @@ await TestHelper.WaitForConditionAsync(
         Assert.NotNull(task);
         Assert.Contains("TASK_AGENT_DONE", task.LatestResponse ?? task.Result ?? string.Empty);
 
-        if (task.Status == GitHub.Copilot.SDK.Rpc.TaskStatus.Idle)
+        if (task.Status == GitHub.Copilot.Rpc.TaskStatus.Idle)
         {
             var cancel = await session.Rpc.Tasks.CancelAsync(started.AgentId);
             Assert.True(cancel.Cancelled);
diff --git a/dotnet/test/E2E/SessionConfigE2ETests.cs b/dotnet/test/E2E/SessionConfigE2ETests.cs
index 43d6681b7..64f5518fb 100644
--- a/dotnet/test/E2E/SessionConfigE2ETests.cs
+++ b/dotnet/test/E2E/SessionConfigE2ETests.cs
@@ -1,14 +1,14 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using System.Text.Json;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class SessionConfigE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "session_config", output)
@@ -112,7 +112,7 @@ public async Task Should_Use_Custom_SessionId()
 
         Assert.Equal(requestedSessionId, session.SessionId);
 
-        var messages = await session.GetMessagesAsync();
+        var messages = await session.GetEventsAsync();
         var startEvent = Assert.IsType<SessionStartEvent>(messages[0]);
         Assert.Equal(requestedSessionId, startEvent.Data.SessionId);
 
@@ -131,7 +131,7 @@ public async Task Should_Apply_ReasoningEffort_On_Session_Create()
             ReasoningEffort = "high",
         });
 
-        var startEvent = Assert.Single((await session.GetMessagesAsync()).OfType<SessionStartEvent>());
+        var startEvent = Assert.Single((await session.GetEventsAsync()).OfType<SessionStartEvent>());
         Assert.Equal(reasoningModelId, startEvent.Data.SelectedModel);
         Assert.Equal("high", startEvent.Data.ReasoningEffort);
 
@@ -153,7 +153,7 @@ public async Task Should_Apply_All_ReasoningEffort_Values_On_Session_Create(stri
             ReasoningEffort = effort,
         });
 
-        var startEvent = Assert.Single((await session.GetMessagesAsync()).OfType<SessionStartEvent>());
+        var startEvent = Assert.Single((await session.GetEventsAsync()).OfType<SessionStartEvent>());
         Assert.Equal(reasoningModelId, startEvent.Data.SelectedModel);
         Assert.Equal(effort, startEvent.Data.ReasoningEffort);
 
@@ -172,7 +172,7 @@ public async Task Should_Apply_ReasoningEffort_On_Session_Resume()
             ReasoningEffort = "high",
         });
 
-        var resumeEvent = Assert.Single((await resumedSession.GetMessagesAsync()).OfType<SessionResumeEvent>());
+        var resumeEvent = Assert.Single((await resumedSession.GetEventsAsync()).OfType<SessionResumeEvent>());
         Assert.Equal(reasoningModelId, resumeEvent.Data.SelectedModel);
         Assert.Equal("high", resumeEvent.Data.ReasoningEffort);
 
diff --git a/dotnet/test/E2E/SessionE2ETests.cs b/dotnet/test/E2E/SessionE2ETests.cs
index e46581249..7711c86dc 100644
--- a/dotnet/test/E2E/SessionE2ETests.cs
+++ b/dotnet/test/E2E/SessionE2ETests.cs
@@ -1,16 +1,16 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using Microsoft.Extensions.AI;
 using System.Collections.Concurrent;
 using System.ComponentModel;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class SessionE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "session", output)
 {
@@ -21,14 +21,14 @@ public async Task ShouldCreateAndDisconnectSessions()
 
         Assert.Matches(@"^[a-f0-9-]+$", session.SessionId);
 
-        var messages = await session.GetMessagesAsync();
+        var messages = await session.GetEventsAsync();
         Assert.NotEmpty(messages);
         var startEvent = Assert.IsType<SessionStartEvent>(messages[0]);
         Assert.Equal(session.SessionId, startEvent.Data.SessionId);
 
         await session.DisposeAsync();
 
-        await Assert.ThrowsAsync<ObjectDisposedException>(() => session.GetMessagesAsync());
+        await Assert.ThrowsAsync<ObjectDisposedException>(() => session.GetEventsAsync());
     }
 
     [Fact]
@@ -243,7 +243,7 @@ public async Task Should_Resume_A_Session_Using_A_New_Client()
         });
         Assert.Equal(sessionId, session2.SessionId);
 
-        var messages = await session2.GetMessagesAsync();
+        var messages = await session2.GetEventsAsync();
         Assert.Contains(messages, m => m is UserMessageEvent);
         var resumeEvent = Assert.Single(messages.OfType<SessionResumeEvent>());
         Assert.True(resumeEvent.Data.ContinuePendingWork);
@@ -284,7 +284,7 @@ await session.SendAsync(new MessageOptions
         await sessionIdleTask;
 
         // The session should still be alive and usable after abort
-        var messages = await session.GetMessagesAsync();
+        var messages = await session.GetEventsAsync();
         Assert.NotEmpty(messages);
 
         // Verify an abort event exists in messages
@@ -324,7 +324,7 @@ public async Task Should_Receive_Session_Events()
         var concurrentCount = 0;
         var maxConcurrent = 0;
 
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             // Track concurrent handler invocations to verify serial dispatch.
             var current = Interlocked.Increment(ref concurrentCount);
@@ -393,7 +393,7 @@ public async Task Send_Returns_Immediately_While_Events_Stream_In_Background()
         });
         var events = new ConcurrentQueue<string>();
 
-        session.On(evt => events.Enqueue(evt.Type));
+        session.On<SessionEvent>(evt => events.Enqueue(evt.Type));
 
         // Use a slow command so we can verify SendAsync() returns before completion
         await session.SendAsync(new MessageOptions { Prompt = "Run 'sleep 2 && echo done'" });
@@ -415,7 +415,7 @@ public async Task SendAndWait_Blocks_Until_Session_Idle_And_Returns_Final_Assist
         var session = await CreateSessionAsync();
         var events = new ConcurrentQueue<string>();
 
-        session.On(evt => events.Enqueue(evt.Type));
+        session.On<SessionEvent>(evt => events.Enqueue(evt.Type));
 
         var response = await session.SendAndWaitAsync(new MessageOptions { Prompt = "What is 2+2?" });
 
@@ -581,7 +581,7 @@ public async Task Should_Log_Messages_At_Various_Levels()
         var session = await CreateSessionAsync();
         var events = new List<SessionEvent>();
         var eventsLock = new object();
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             lock (eventsLock)
             {
@@ -640,7 +640,7 @@ public async Task Handler_Exception_Does_Not_Halt_Event_Delivery()
         var eventCount = 0;
         var gotIdle = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
 
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             eventCount++;
 
@@ -666,7 +666,7 @@ public async Task DisposeAsync_From_Handler_Does_Not_Deadlock()
         var session = await CreateSessionAsync();
         var disposed = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
 
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             if (evt is UserMessageEvent)
             {
@@ -728,7 +728,7 @@ await session.SendAndWaitAsync(new MessageOptions
             ],
         });
 
-        var userMessage = (await session.GetMessagesAsync()).OfType<UserMessageEvent>().Last();
+        var userMessage = (await session.GetEventsAsync()).OfType<UserMessageEvent>().Last();
         var attachment = Assert.IsType<UserMessageAttachmentFile>(Assert.Single(userMessage.Data.Attachments!));
         Assert.Equal("attached-file.txt", attachment.DisplayName);
         Assert.Equal(filePath, attachment.Path);
@@ -758,7 +758,7 @@ await session.SendAndWaitAsync(new MessageOptions
             ],
         });
 
-        var userMessage = (await session.GetMessagesAsync()).OfType<UserMessageEvent>().Last();
+        var userMessage = (await session.GetEventsAsync()).OfType<UserMessageEvent>().Last();
         var attachment = Assert.IsType<UserMessageAttachmentDirectory>(Assert.Single(userMessage.Data.Attachments!));
         Assert.Equal("attached-directory", attachment.DisplayName);
         Assert.Equal(directoryPath, attachment.Path);
@@ -791,7 +791,7 @@ await session.SendAndWaitAsync(new MessageOptions
             ],
         });
 
-        var userMessage = (await session.GetMessagesAsync()).OfType<UserMessageEvent>().Last();
+        var userMessage = (await session.GetEventsAsync()).OfType<UserMessageEvent>().Last();
         var attachment = Assert.IsType<UserMessageAttachmentSelection>(Assert.Single(userMessage.Data.Attachments!));
         Assert.Equal("selected-file.cs", attachment.DisplayName);
         Assert.Equal(filePath, attachment.FilePath);
@@ -823,7 +823,7 @@ await session.SendAndWaitAsync(new MessageOptions
             ],
         });
 
-        var userMessage = (await session.GetMessagesAsync()).OfType<UserMessageEvent>().Last();
+        var userMessage = (await session.GetEventsAsync()).OfType<UserMessageEvent>().Last();
         var attachment = Assert.IsType<UserMessageAttachmentGithubReference>(Assert.Single(userMessage.Data.Attachments!));
         Assert.Equal(1234, attachment.Number);
         Assert.Equal(UserMessageAttachmentGithubReferenceType.Issue, attachment.ReferenceType);
@@ -843,7 +843,7 @@ await session.SendAndWaitAsync(new MessageOptions
             Mode = "plan",
         });
 
-        var userMessage = (await session.GetMessagesAsync()).OfType<UserMessageEvent>().Last();
+        var userMessage = (await session.GetEventsAsync()).OfType<UserMessageEvent>().Last();
         Assert.Equal("Say mode ok.", userMessage.Data.Content);
         // The current runtime accepts the per-message mode option but does not echo it on user.message.
         Assert.Null(userMessage.Data.AgentMode);
diff --git a/dotnet/test/E2E/SessionFsE2ETests.cs b/dotnet/test/E2E/SessionFsE2ETests.cs
index 7649c160c..812fc8997 100644
--- a/dotnet/test/E2E/SessionFsE2ETests.cs
+++ b/dotnet/test/E2E/SessionFsE2ETests.cs
@@ -1,14 +1,14 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using Microsoft.Extensions.AI;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class SessionFsE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "session_fs", output)
@@ -31,7 +31,7 @@ public async Task Should_Route_File_Operations_Through_The_Session_Fs_Provider()
             var session = await client.CreateSessionAsync(new SessionConfig
             {
                 OnPermissionRequest = PermissionHandler.ApproveAll,
-                CreateSessionFsHandler = s => new TestSessionFsHandler(s.SessionId, providerRoot),
+                CreateSessionFsProvider = s => new TestSessionFsHandler(s.SessionId, providerRoot),
             });
 
             var msg = await session.SendAndWaitAsync(new MessageOptions { Prompt = "What is 100 + 200?" });
@@ -61,7 +61,7 @@ public async Task Should_Load_Session_Data_From_Fs_Provider_On_Resume()
             var session1 = await client.CreateSessionAsync(new SessionConfig
             {
                 OnPermissionRequest = PermissionHandler.ApproveAll,
-                CreateSessionFsHandler = createSessionFsHandler,
+                CreateSessionFsProvider = createSessionFsHandler,
             });
             var sessionId = session1.SessionId;
 
@@ -75,7 +75,7 @@ public async Task Should_Load_Session_Data_From_Fs_Provider_On_Resume()
             var session2 = await client.ResumeSessionAsync(sessionId, new ResumeSessionConfig
             {
                 OnPermissionRequest = PermissionHandler.ApproveAll,
-                CreateSessionFsHandler = createSessionFsHandler,
+                CreateSessionFsProvider = createSessionFsHandler,
             });
 
             var msg2 = await session2.SendAndWaitAsync(new MessageOptions { Prompt = "What is that times 3?" });
@@ -100,20 +100,18 @@ public async Task Should_Reject_SetProvider_When_Sessions_Already_Exist()
             _ = await client1.CreateSessionAsync(new SessionConfig
             {
                 OnPermissionRequest = PermissionHandler.ApproveAll,
-                CreateSessionFsHandler = createSessionFsHandler,
+                CreateSessionFsProvider = createSessionFsHandler,
             });
 
-            var port = client1.ActualPort
-                ?? throw new InvalidOperationException("Client1 is not using TCP mode; ActualPort is null");
+            var port = client1.RuntimePort
+                ?? throw new InvalidOperationException("Client1 is not using TCP mode; RuntimePort is null");
 
             var client2 = Ctx.CreateClient(
-                useStdio: false,
                 options: new CopilotClientOptions
                 {
-                    CliUrl = $"localhost:{port}",
-                    LogLevel = "error",
+                    LogLevel = CopilotLogLevel.Error,
                     SessionFs = SessionFsConfig,
-                    TcpConnectionToken = "session-fs-shared-token",
+                    Connection = RuntimeConnection.ForUri($"localhost:{port}", connectionToken: "session-fs-shared-token"),
                 });
 
             try
@@ -324,7 +322,7 @@ public async Task Should_Map_Large_Output_Handling_Into_SessionFs()
             var session = await client.CreateSessionAsync(new SessionConfig
             {
                 OnPermissionRequest = PermissionHandler.ApproveAll,
-                CreateSessionFsHandler = s => new TestSessionFsHandler(s.SessionId, providerRoot),
+                CreateSessionFsProvider = s => new TestSessionFsHandler(s.SessionId, providerRoot),
                 Tools =
                 [
                     AIFunctionFactory.Create(() => suppliedFileContent, "get_big_string", "Returns a large string")
@@ -336,7 +334,7 @@ await session.SendAndWaitAsync(new MessageOptions
                 Prompt = "Call the get_big_string tool and reply with the word DONE only.",
             });
 
-            var messages = await session.GetMessagesAsync();
+            var messages = await session.GetEventsAsync();
             var toolResult = FindToolCallResult(messages, "get_big_string");
             Assert.NotNull(toolResult);
             Assert.Contains($"{SessionFsConfig.SessionStatePath}/temp/", toolResult);
@@ -366,11 +364,11 @@ public async Task Should_Succeed_With_Compaction_While_Using_SessionFs()
             var session = await client.CreateSessionAsync(new SessionConfig
             {
                 OnPermissionRequest = PermissionHandler.ApproveAll,
-                CreateSessionFsHandler = s => new TestSessionFsHandler(s.SessionId, providerRoot),
+                CreateSessionFsProvider = s => new TestSessionFsHandler(s.SessionId, providerRoot),
             });
 
             SessionCompactionCompleteEvent? compactionEvent = null;
-            using var _ = session.On(evt =>
+            using var _ = session.On<SessionEvent>(evt =>
             {
                 if (evt is SessionCompactionCompleteEvent complete)
                 {
@@ -405,7 +403,7 @@ public async Task Should_Write_Workspace_Metadata_Via_SessionFs()
             var session = await client.CreateSessionAsync(new SessionConfig
             {
                 OnPermissionRequest = PermissionHandler.ApproveAll,
-                CreateSessionFsHandler = s => new TestSessionFsHandler(s.SessionId, providerRoot),
+                CreateSessionFsProvider = s => new TestSessionFsHandler(s.SessionId, providerRoot),
             });
 
             var msg = await session.SendAndWaitAsync(new MessageOptions { Prompt = "What is 7 * 8?" });
@@ -436,7 +434,7 @@ public async Task Should_Persist_Plan_Md_Via_SessionFs()
             var session = await client.CreateSessionAsync(new SessionConfig
             {
                 OnPermissionRequest = PermissionHandler.ApproveAll,
-                CreateSessionFsHandler = s => new TestSessionFsHandler(s.SessionId, providerRoot),
+                CreateSessionFsProvider = s => new TestSessionFsHandler(s.SessionId, providerRoot),
             });
 
             // Write a plan via the session RPC
@@ -457,13 +455,16 @@ public async Task Should_Persist_Plan_Md_Via_SessionFs()
 
     private CopilotClient CreateSessionFsClient(string providerRoot, bool useStdio = true, string? tcpConnectionToken = null)
     {
+        RuntimeConnection connection = useStdio
+            ? RuntimeConnection.ForStdio()
+            : RuntimeConnection.ForTcp(connectionToken: tcpConnectionToken);
+
         Directory.CreateDirectory(providerRoot);
         return Ctx.CreateClient(
-            useStdio: useStdio,
             options: new CopilotClientOptions
             {
                 SessionFs = SessionFsConfig,
-                TcpConnectionToken = tcpConnectionToken,
+                Connection = connection,
             });
     }
 
@@ -593,16 +594,16 @@ protected override Task<bool> ExistsAsync(string path, CancellationToken cancell
         protected override Task<SessionFsStatResult> StatAsync(string path, CancellationToken cancellationToken) =>
             Task.FromException<SessionFsStatResult>(exception);
 
-        protected override Task MkdirAsync(string path, bool recursive, int? mode, CancellationToken cancellationToken) =>
+        protected override Task MakeDirectoryAsync(string path, bool recursive, int? mode, CancellationToken cancellationToken) =>
             Task.FromException(exception);
 
-        protected override Task<IList<string>> ReaddirAsync(string path, CancellationToken cancellationToken) =>
+        protected override Task<IList<string>> ReadDirectoryAsync(string path, CancellationToken cancellationToken) =>
             Task.FromException<IList<string>>(exception);
 
-        protected override Task<IList<SessionFsReaddirWithTypesEntry>> ReaddirWithTypesAsync(string path, CancellationToken cancellationToken) =>
+        protected override Task<IList<SessionFsReaddirWithTypesEntry>> ReadDirectoryWithTypesAsync(string path, CancellationToken cancellationToken) =>
             Task.FromException<IList<SessionFsReaddirWithTypesEntry>>(exception);
 
-        protected override Task RmAsync(string path, bool recursive, bool force, CancellationToken cancellationToken) =>
+        protected override Task RemoveAsync(string path, bool recursive, bool force, CancellationToken cancellationToken) =>
             Task.FromException(exception);
 
         protected override Task RenameAsync(string src, string dest, CancellationToken cancellationToken) =>
@@ -674,13 +675,13 @@ protected override Task<SessionFsStatResult> StatAsync(string path, Cancellation
             });
         }
 
-        protected override Task MkdirAsync(string path, bool recursive, int? mode, CancellationToken cancellationToken)
+        protected override Task MakeDirectoryAsync(string path, bool recursive, int? mode, CancellationToken cancellationToken)
         {
             Directory.CreateDirectory(ResolvePath(path));
             return Task.CompletedTask;
         }
 
-        protected override Task<IList<string>> ReaddirAsync(string path, CancellationToken cancellationToken)
+        protected override Task<IList<string>> ReadDirectoryAsync(string path, CancellationToken cancellationToken)
         {
             IList<string> entries = Directory
                 .EnumerateFileSystemEntries(ResolvePath(path))
@@ -691,7 +692,7 @@ protected override Task<IList<string>> ReaddirAsync(string path, CancellationTok
             return Task.FromResult(entries);
         }
 
-        protected override Task<IList<SessionFsReaddirWithTypesEntry>> ReaddirWithTypesAsync(string path, CancellationToken cancellationToken)
+        protected override Task<IList<SessionFsReaddirWithTypesEntry>> ReadDirectoryWithTypesAsync(string path, CancellationToken cancellationToken)
         {
             IList<SessionFsReaddirWithTypesEntry> entries = Directory
                 .EnumerateFileSystemEntries(ResolvePath(path))
@@ -704,7 +705,7 @@ protected override Task<IList<SessionFsReaddirWithTypesEntry>> ReaddirWithTypesA
             return Task.FromResult(entries);
         }
 
-        protected override Task RmAsync(string path, bool recursive, bool force, CancellationToken cancellationToken)
+        protected override Task RemoveAsync(string path, bool recursive, bool force, CancellationToken cancellationToken)
         {
             var fullPath = ResolvePath(path);
 
diff --git a/dotnet/test/E2E/SessionFsSqliteE2ETests.cs b/dotnet/test/E2E/SessionFsSqliteE2ETests.cs
index f495fca3d..9caa624af 100644
--- a/dotnet/test/E2E/SessionFsSqliteE2ETests.cs
+++ b/dotnet/test/E2E/SessionFsSqliteE2ETests.cs
@@ -1,13 +1,13 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class SessionFsSqliteE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "session_fs_sqlite", output)
@@ -30,7 +30,7 @@ public async Task Should_Route_Sql_Queries_Through_The_Sessionfs_Sqlite_Handler(
         var session = await client.CreateSessionAsync(new SessionConfig
         {
             OnPermissionRequest = PermissionHandler.ApproveAll,
-            CreateSessionFsHandler = s => new InMemorySessionFsSqliteHandler(s.SessionId, _sqliteCalls),
+            CreateSessionFsProvider = s => new InMemorySessionFsSqliteHandler(s.SessionId, _sqliteCalls),
         });
 
         var msg = await session.SendAndWaitAsync(new MessageOptions
@@ -60,7 +60,7 @@ public async Task Should_Allow_Subagents_To_Use_Sql_Tool_Via_Inherited_Sessionfs
         var session = await client.CreateSessionAsync(new SessionConfig
         {
             OnPermissionRequest = PermissionHandler.ApproveAll,
-            CreateSessionFsHandler = s =>
+            CreateSessionFsProvider = s =>
             {
                 handler = new InMemorySessionFsSqliteHandler(s.SessionId, _sqliteCalls);
                 return handler;
@@ -68,7 +68,7 @@ public async Task Should_Allow_Subagents_To_Use_Sql_Tool_Via_Inherited_Sessionfs
         });
 
         var events = new List<SessionEvent>();
-        using var _ = session.On(evt => events.Add(evt));
+        using var _ = session.On<SessionEvent>(evt => events.Add(evt));
 
         await session.SendAndWaitAsync(new MessageOptions
         {
diff --git a/dotnet/test/E2E/SessionLifecycleE2ETests.cs b/dotnet/test/E2E/SessionLifecycleE2ETests.cs
index 19134cb53..31532def2 100644
--- a/dotnet/test/E2E/SessionLifecycleE2ETests.cs
+++ b/dotnet/test/E2E/SessionLifecycleE2ETests.cs
@@ -1,12 +1,12 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// Lifecycle coverage at the <see cref="CopilotClient"/> level: listing
@@ -84,7 +84,7 @@ await session.SendAndWaitAsync(new MessageOptions
             Prompt = "What is 2+2? Reply with just the number.",
         });
 
-        var messages = await session.GetMessagesAsync();
+        var messages = await session.GetEventsAsync();
         Assert.NotEmpty(messages);
 
         // Should have at least session.start, user.message, assistant.message
@@ -130,8 +130,8 @@ public async Task Should_Isolate_Events_Between_Concurrent_Sessions()
         var session1Events = new List<SessionEvent>();
         var session2Events = new List<SessionEvent>();
 
-        session1.On(evt => { lock (session1Events) { session1Events.Add(evt); } });
-        session2.On(evt => { lock (session2Events) { session2Events.Add(evt); } });
+        session1.On<SessionEvent>(evt => { lock (session1Events) { session1Events.Add(evt); } });
+        session2.On<SessionEvent>(evt => { lock (session2Events) { session2Events.Add(evt); } });
 
         // Send to both sessions
         await session1.SendAndWaitAsync(new MessageOptions
diff --git a/dotnet/test/E2E/SessionMcpAndAgentConfigE2ETests.cs b/dotnet/test/E2E/SessionMcpAndAgentConfigE2ETests.cs
index cc528b219..9567c98be 100644
--- a/dotnet/test/E2E/SessionMcpAndAgentConfigE2ETests.cs
+++ b/dotnet/test/E2E/SessionMcpAndAgentConfigE2ETests.cs
@@ -2,12 +2,12 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Rpc;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Rpc;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class SessionMcpAndAgentConfigE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "mcp_and_agents", output)
 {
@@ -297,7 +297,7 @@ public async Task Should_Pass_Literal_Env_Values_To_Mcp_Server_Subprocess()
                 Command = "node",
                 Args = [Path.Combine(testHarnessDir, "test-mcp-server.mjs")],
                 Env = new Dictionary<string, string> { ["TEST_SECRET"] = "hunter2" },
-                Cwd = testHarnessDir,
+                WorkingDirectory = testHarnessDir,
                 Tools = ["*"]
             }
         };
@@ -358,7 +358,7 @@ await File.WriteAllTextAsync(
                     "--config",
                     configPath
                 ],
-                Cwd = testHarnessDir,
+                WorkingDirectory = testHarnessDir,
                 Tools = ["*"]
             }
         };
diff --git a/dotnet/test/E2E/SkillsE2ETests.cs b/dotnet/test/E2E/SkillsE2ETests.cs
index 7da1d4b3e..76f84106f 100644
--- a/dotnet/test/E2E/SkillsE2ETests.cs
+++ b/dotnet/test/E2E/SkillsE2ETests.cs
@@ -5,7 +5,7 @@
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class SkillsE2ETests : E2ETestBase
 {
diff --git a/dotnet/test/E2E/StreamingFidelityE2ETests.cs b/dotnet/test/E2E/StreamingFidelityE2ETests.cs
index 82580a656..fec00f1cb 100644
--- a/dotnet/test/E2E/StreamingFidelityE2ETests.cs
+++ b/dotnet/test/E2E/StreamingFidelityE2ETests.cs
@@ -1,11 +1,11 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class StreamingFidelityE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "streaming_fidelity", output)
 {
@@ -15,7 +15,7 @@ public async Task Should_Produce_Delta_Events_When_Streaming_Is_Enabled()
         var session = await CreateSessionAsync(new SessionConfig { Streaming = true });
 
         var events = new List<SessionEvent>();
-        session.On(evt => { lock (events) { events.Add(evt); } });
+        session.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         await session.SendAndWaitAsync(new MessageOptions { Prompt = "Count from 1 to 5, separated by commas." });
 
@@ -51,7 +51,7 @@ public async Task Should_Not_Produce_Deltas_When_Streaming_Is_Disabled()
         var session = await CreateSessionAsync(new SessionConfig { Streaming = false });
 
         var events = new List<SessionEvent>();
-        session.On(evt => { lock (events) { events.Add(evt); } });
+        session.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         await session.SendAndWaitAsync(new MessageOptions { Prompt = "Say 'hello world'." });
 
@@ -83,7 +83,7 @@ public async Task Should_Produce_Deltas_After_Session_Resume()
             new ResumeSessionConfig { OnPermissionRequest = PermissionHandler.ApproveAll, Streaming = true });
 
         var events = new List<SessionEvent>();
-        session2.On(evt => { lock (events) { events.Add(evt); } });
+        session2.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         var answer = await session2.SendAndWaitAsync(new MessageOptions { Prompt = "Now if you double that, what do you get?" });
         Assert.NotNull(answer);
@@ -118,7 +118,7 @@ public async Task Should_Not_Produce_Deltas_After_Session_Resume_With_Streaming_
             new ResumeSessionConfig { OnPermissionRequest = PermissionHandler.ApproveAll, Streaming = false });
 
         var events = new List<SessionEvent>();
-        session2.On(evt => { lock (events) { events.Add(evt); } });
+        session2.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         var answer = await session2.SendAndWaitAsync(new MessageOptions { Prompt = "Now if you double that, what do you get?" });
         Assert.NotNull(answer);
@@ -150,7 +150,7 @@ public async Task Should_Emit_Streaming_Deltas_With_Reasoning_Effort_Configured(
         });
 
         var events = new List<SessionEvent>();
-        session.On(evt => { lock (events) { events.Add(evt); } });
+        session.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         await session.SendAndWaitAsync(new MessageOptions { Prompt = "What is 15 * 17?" });
 
@@ -167,7 +167,7 @@ public async Task Should_Emit_Streaming_Deltas_With_Reasoning_Effort_Configured(
         Assert.Contains("255", assistantEvents.Last().Data.Content ?? string.Empty);
 
         // Verify the session was created with reasoning effort via GetMessages
-        var messages = await session.GetMessagesAsync();
+        var messages = await session.GetEventsAsync();
         var startEvent = Assert.Single(messages.OfType<SessionStartEvent>());
         Assert.Equal("high", startEvent.Data.ReasoningEffort);
 
@@ -180,7 +180,7 @@ public async Task Should_Emit_AssistantMessageStart_Before_Deltas_With_Matching_
         var session = await CreateSessionAsync(new SessionConfig { Streaming = true });
 
         var events = new List<SessionEvent>();
-        session.On(evt => { lock (events) { events.Add(evt); } });
+        session.On<SessionEvent>(evt => { lock (events) { events.Add(evt); } });
 
         await session.SendAndWaitAsync(new MessageOptions { Prompt = "Count from 1 to 5, separated by commas." });
 
diff --git a/dotnet/test/E2E/SubagentHooksE2ETests.cs b/dotnet/test/E2E/SubagentHooksE2ETests.cs
index 1a9c8ffa1..5c8543215 100644
--- a/dotnet/test/E2E/SubagentHooksE2ETests.cs
+++ b/dotnet/test/E2E/SubagentHooksE2ETests.cs
@@ -3,11 +3,11 @@
  *--------------------------------------------------------------------------------------------*/
 
 using System.Collections.Concurrent;
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class SubagentHooksE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "subagent_hooks", output)
diff --git a/dotnet/test/E2E/SuspendE2ETests.cs b/dotnet/test/E2E/SuspendE2ETests.cs
index 44dcef7dd..d3aa8067d 100644
--- a/dotnet/test/E2E/SuspendE2ETests.cs
+++ b/dotnet/test/E2E/SuspendE2ETests.cs
@@ -7,7 +7,7 @@
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 /// <summary>
 /// E2E coverage for the <c>session.suspend</c> RPC. Suspend is a graceful shutdown
@@ -50,12 +50,12 @@ public async Task Should_Suspend_Idle_Session_Without_Throwing()
     public async Task Should_Allow_Resume_And_Continue_Conversation_After_Suspend()
     {
         const string sharedToken = "suspend-shared-token";
-        await using var server = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions { TcpConnectionToken = sharedToken });
+        await using var server = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForTcp(connectionToken: sharedToken) });
         await server.StartAsync();
         var cliUrl = GetCliUrl(server);
 
         string sessionId;
-        await using (var client1 = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = sharedToken }))
+        await using (var client1 = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: sharedToken) }))
         {
             var session1 = await client1.CreateSessionAsync(new SessionConfig
             {
@@ -76,7 +76,7 @@ await session1.SendAndWaitAsync(new MessageOptions
 
         // A different client should be able to pick the session back up. The previous
         // turn was completed before suspend, so there is no pending work to continue.
-        await using var client2 = Ctx.CreateClient(options: new CopilotClientOptions { CliUrl = cliUrl, TcpConnectionToken = sharedToken });
+        await using var client2 = Ctx.CreateClient(options: new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl, connectionToken: sharedToken) });
         var session2 = await client2.ResumeSessionAsync(sessionId, new ResumeSessionConfig
         {
             OnPermissionRequest = PermissionHandler.ApproveAll,
@@ -175,7 +175,7 @@ public async Task Should_Reject_Pending_External_Tool_When_Suspending()
             OnPermissionRequest = PermissionHandler.ApproveAll,
         });
 
-        using var subscription = session.On(evt =>
+        using var subscription = session.On<SessionEvent>(evt =>
         {
             if (evt is ExternalToolRequestedEvent ext && ext.Data.ToolName == "suspend_reject_external_tool")
             {
@@ -219,7 +219,7 @@ async Task<string> BlockingTool([Description("Value to look up")] string value)
 
     private static string GetCliUrl(CopilotClient client)
     {
-        var port = client.ActualPort
+        var port = client.RuntimePort
             ?? throw new InvalidOperationException("Expected the test server to be listening on a TCP port.");
         return $"localhost:{port}";
     }
diff --git a/dotnet/test/E2E/SystemMessageTransformE2ETests.cs b/dotnet/test/E2E/SystemMessageTransformE2ETests.cs
index 5af704834..91f942190 100644
--- a/dotnet/test/E2E/SystemMessageTransformE2ETests.cs
+++ b/dotnet/test/E2E/SystemMessageTransformE2ETests.cs
@@ -2,11 +2,11 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class SystemMessageTransformE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "system_message_transform", output)
 {
diff --git a/dotnet/test/E2E/TelemetryExportE2ETests.cs b/dotnet/test/E2E/TelemetryExportE2ETests.cs
index b4fced4e2..ceec2326e 100644
--- a/dotnet/test/E2E/TelemetryExportE2ETests.cs
+++ b/dotnet/test/E2E/TelemetryExportE2ETests.cs
@@ -2,13 +2,13 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Microsoft.Extensions.AI;
 using System.Text.Json;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public class TelemetryExportE2ETests(E2ETestFixture fixture, ITestOutputHelper output)
     : E2ETestBase(fixture, "telemetry", output)
diff --git a/dotnet/test/E2E/ToolResultsE2ETests.cs b/dotnet/test/E2E/ToolResultsE2ETests.cs
index c1283baa5..75fd9488e 100644
--- a/dotnet/test/E2E/ToolResultsE2ETests.cs
+++ b/dotnet/test/E2E/ToolResultsE2ETests.cs
@@ -2,7 +2,7 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Microsoft.Extensions.AI;
 using System.ComponentModel;
 using System.Text.Json;
@@ -10,7 +10,7 @@
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public partial class ToolResultsE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "tool_results", output)
 {
@@ -131,7 +131,7 @@ public async Task Should_Handle_Tool_Result_With_Rejected_ResultType()
             OnPermissionRequest = PermissionHandler.ApproveAll,
         });
 
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             if (evt is ToolExecutionCompleteEvent toolEvt)
             {
@@ -181,7 +181,7 @@ public async Task Should_Handle_Tool_Result_With_Denied_ResultType()
             OnPermissionRequest = PermissionHandler.ApproveAll,
         });
 
-        session.On(evt =>
+        session.On<SessionEvent>(evt =>
         {
             if (evt is ToolExecutionCompleteEvent toolEvt)
             {
diff --git a/dotnet/test/E2E/ToolsE2ETests.cs b/dotnet/test/E2E/ToolsE2ETests.cs
index 529223894..c36bf2294 100644
--- a/dotnet/test/E2E/ToolsE2ETests.cs
+++ b/dotnet/test/E2E/ToolsE2ETests.cs
@@ -2,7 +2,7 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Microsoft.Extensions.AI;
 using System.Collections.ObjectModel;
 using System.ComponentModel;
@@ -11,7 +11,7 @@
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test.E2E;
+namespace GitHub.Copilot.Test.E2E;
 
 public partial class ToolsE2ETests(E2ETestFixture fixture, ITestOutputHelper output) : E2ETestBase(fixture, "tools", output)
 {
@@ -240,7 +240,7 @@ await session.SendAsync(new MessageOptions
             BinaryResultsForLlm = [new() {
                 // 2x2 yellow square
                 Data = "iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAIAAAD91JpzAAAADklEQVR4nGP4/5/h/38GABkAA/0k+7UAAAAASUVORK5CYII=",
-                Type = "base64",
+                Type = ToolBinaryResultType.Image,
                 MimeType = "image/png",
             }],
             SessionLog = "Returned an image",
diff --git a/dotnet/test/GitHub.Copilot.SDK.Test.csproj b/dotnet/test/GitHub.Copilot.SDK.Test.csproj
index cdff9b014..57f89bcd9 100644
--- a/dotnet/test/GitHub.Copilot.SDK.Test.csproj
+++ b/dotnet/test/GitHub.Copilot.SDK.Test.csproj
@@ -3,6 +3,7 @@
   <PropertyGroup>
     <TargetFrameworks>net8.0</TargetFrameworks>
     <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('Windows'))">net8.0;net472</TargetFrameworks>
+    <RootNamespace>GitHub.Copilot.Test</RootNamespace>
     <IsPackable>false</IsPackable>
     <IsTestProject>true</IsTestProject>
     <NoWarn>$(NoWarn);GHCP001</NoWarn>
diff --git a/dotnet/test/Harness/CapiProxy.cs b/dotnet/test/Harness/CapiProxy.cs
index 274055540..9b80651bc 100644
--- a/dotnet/test/Harness/CapiProxy.cs
+++ b/dotnet/test/Harness/CapiProxy.cs
@@ -10,7 +10,7 @@
 using System.Text.Json.Serialization;
 using System.Text.RegularExpressions;
 
-namespace GitHub.Copilot.SDK.Test.Harness;
+namespace GitHub.Copilot.Test.Harness;
 
 public sealed partial class CapiProxy : IAsyncDisposable
 {
diff --git a/dotnet/test/Harness/E2ETestBase.cs b/dotnet/test/Harness/E2ETestBase.cs
index ca5d2b816..592253bda 100644
--- a/dotnet/test/Harness/E2ETestBase.cs
+++ b/dotnet/test/Harness/E2ETestBase.cs
@@ -2,14 +2,14 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Microsoft.Extensions.Logging;
 using System.Data;
 using System.Reflection;
 using Xunit;
 using Xunit.Abstractions;
 
-namespace GitHub.Copilot.SDK.Test;
+namespace GitHub.Copilot.Test;
 
 public abstract class E2ETestBase : IClassFixture<E2ETestFixture>, IAsyncLifetime
 {
@@ -88,13 +88,12 @@ protected async Task<CopilotSession> ResumeSessionAsync(string sessionId, Resume
         config.OnPermissionRequest ??= PermissionHandler.ApproveAll;
 
         await Client.StartAsync();
-        var port = Client.ActualPort
+        var port = Client.RuntimePort
             ?? throw new InvalidOperationException("The shared E2E client must use TCP transport to support multi-client resume.");
 
         var client = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            CliUrl = $"localhost:{port}",
-            TcpConnectionToken = E2ETestFixture.SharedTcpConnectionToken,
+            Connection = RuntimeConnection.ForUri($"localhost:{port}", connectionToken: E2ETestFixture.SharedTcpConnectionToken),
         });
         return await client.ResumeSessionAsync(sessionId, config);
     }
diff --git a/dotnet/test/Harness/E2ETestContext.cs b/dotnet/test/Harness/E2ETestContext.cs
index ef703c4be..1819eb634 100644
--- a/dotnet/test/Harness/E2ETestContext.cs
+++ b/dotnet/test/Harness/E2ETestContext.cs
@@ -3,10 +3,11 @@
  *--------------------------------------------------------------------------------------------*/
 
 using Microsoft.Extensions.Logging;
+using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Text.RegularExpressions;
 
-namespace GitHub.Copilot.SDK.Test.Harness;
+namespace GitHub.Copilot.Test.Harness;
 
 public sealed class E2ETestContext : IAsyncDisposable
 {
@@ -195,15 +196,19 @@ public IReadOnlyDictionary<string, string> GetEnvironment()
             env["GH_ENTERPRISE_TOKEN"] = "";
             env["GITHUB_ENTERPRISE_TOKEN"] = "";
         }
-        if (Environment.GetEnvironmentVariable("GITHUB_ACTIONS") == "true")
-        {
-            env["GH_TOKEN"] = DefaultGitHubToken;
-            env["GITHUB_TOKEN"] = DefaultGitHubToken;
-        }
+
+        env["GITHUB_TOKEN"] = env["GH_TOKEN"] = DefaultGitHubToken;
 
         return env!;
     }
 
+    private static string? GetEffectiveGitHubTokenForTests()
+    {
+        return Environment.GetEnvironmentVariable("GITHUB_ACTIONS") == "true"
+            ? DefaultGitHubToken
+            : Environment.GetEnvironmentVariable("GITHUB_TOKEN");
+    }
+
     public CopilotClient CreateClient(
         bool? useStdio = null,
         CopilotClientOptions? options = null,
@@ -212,21 +217,41 @@ public CopilotClient CreateClient(
     {
         options ??= new CopilotClientOptions();
 
-        options.Cwd ??= WorkDir;
+        options.WorkingDirectory ??= WorkDir;
         options.Environment ??= GetEnvironment();
-        options.UseStdio = useStdio;
         options.Logger ??= Logger;
 
-        if (string.IsNullOrEmpty(options.CliUrl))
+        // Build the connection. If the caller supplied one, just ensure the runtime path is set;
+        // otherwise default to Stdio with the bundled runtime (matches CopilotClient's own default).
+        // useStdio is a convenience shortcut for the no-Connection case; passing both is ambiguous.
+        if (useStdio is not null && options.Connection is not null)
+        {
+            throw new ArgumentException(
+                "Specify either useStdio or options.Connection, not both. " +
+                "Use options.Connection (e.g. RuntimeConnection.ForStdio() / RuntimeConnection.ForTcp()) to control transport when supplying a Connection.",
+                nameof(useStdio));
+        }
+
+        var cliPath = GetCliPath(_repoRoot);
+        switch (options.Connection)
         {
-            options.CliPath ??= GetCliPath(_repoRoot);
+            case null:
+                options.Connection = useStdio == false
+                    ? RuntimeConnection.ForTcp(path: cliPath)
+                    : RuntimeConnection.ForStdio(path: cliPath);
+                break;
+            case ChildProcessRuntimeConnection child when child.Path is null:
+                child.Path = cliPath;
+                break;
         }
 
+        // Auto-inject auth token unless connecting to an existing runtime via URI.
+        var isExistingRuntime = options.Connection is UriRuntimeConnection;
         if (autoInjectGitHubToken
             && string.IsNullOrEmpty(options.GitHubToken)
-            && string.IsNullOrEmpty(options.CliUrl))
+            && !isExistingRuntime)
         {
-            options.GitHubToken = DefaultGitHubToken;
+            options.GitHubToken = GetEffectiveGitHubTokenForTests();
         }
 
         var client = new CopilotClient(options);
diff --git a/dotnet/test/Harness/E2ETestFixture.cs b/dotnet/test/Harness/E2ETestFixture.cs
index a53e4bd32..95bebc139 100644
--- a/dotnet/test/Harness/E2ETestFixture.cs
+++ b/dotnet/test/Harness/E2ETestFixture.cs
@@ -2,10 +2,10 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-using GitHub.Copilot.SDK.Test.Harness;
+using GitHub.Copilot.Test.Harness;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test;
+namespace GitHub.Copilot.Test;
 
 public class E2ETestFixture : IAsyncLifetime
 {
@@ -17,9 +17,9 @@ public class E2ETestFixture : IAsyncLifetime
     public async Task InitializeAsync()
     {
         Ctx = await E2ETestContext.CreateAsync();
-        Client = Ctx.CreateClient(useStdio: false, options: new CopilotClientOptions
+        Client = Ctx.CreateClient(options: new CopilotClientOptions
         {
-            TcpConnectionToken = SharedTcpConnectionToken,
+            Connection = RuntimeConnection.ForTcp(connectionToken: SharedTcpConnectionToken),
         }, persistent: true);
     }
 
diff --git a/dotnet/test/Harness/TestHelper.cs b/dotnet/test/Harness/TestHelper.cs
index 1afd21d3c..5d5839618 100644
--- a/dotnet/test/Harness/TestHelper.cs
+++ b/dotnet/test/Harness/TestHelper.cs
@@ -1,8 +1,8 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
-namespace GitHub.Copilot.SDK.Test.Harness;
+namespace GitHub.Copilot.Test.Harness;
 
 public static class TestHelper
 {
@@ -40,7 +40,7 @@ void TryComplete()
             if (snapshot != null && idle) tcs.TrySetResult(snapshot);
         }
 
-        using var subscription = session.On(evt =>
+        using var subscription = session.On<SessionEvent>(evt =>
         {
             switch (evt)
             {
@@ -91,7 +91,7 @@ async void CheckExistingMessages()
 
     private static async Task<(AssistantMessageEvent? Final, bool SawIdle)> GetExistingMessagesAsync(CopilotSession session, bool alreadyIdle)
     {
-        var messages = (await session.GetMessagesAsync()).ToList();
+        var messages = (await session.GetEventsAsync()).ToList();
 
         var lastUserIdx = messages.FindLastIndex(m => m is UserMessageEvent);
         var currentTurn = lastUserIdx < 0 ? messages : messages.Skip(lastUserIdx).ToList();
@@ -127,7 +127,7 @@ public static async Task<T> GetNextEventOfTypeAsync<T>(
         var tcs = new TaskCompletionSource<T>(TaskCreationOptions.RunContinuationsAsynchronously);
         using var cts = new CancellationTokenSource(timeout ?? DefaultEventTimeout);
 
-        using var subscription = session.On(evt =>
+        using var subscription = session.On<SessionEvent>(evt =>
         {
             if (evt is T matched && predicate(matched))
             {
diff --git a/dotnet/test/Unit/ClientSessionLifetimeTests.cs b/dotnet/test/Unit/ClientSessionLifetimeTests.cs
index cf59b0fbb..5bd3335a5 100644
--- a/dotnet/test/Unit/ClientSessionLifetimeTests.cs
+++ b/dotnet/test/Unit/ClientSessionLifetimeTests.cs
@@ -11,7 +11,7 @@
 using System.Text.Json;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 public sealed class ClientSessionLifetimeTests
 {
@@ -19,7 +19,7 @@ public sealed class ClientSessionLifetimeTests
     public async Task Dropped_Session_Remains_Rooted_By_Client()
     {
         await using var server = await FakeCopilotServer.StartAsync();
-        await using var client = new CopilotClient(new CopilotClientOptions { CliUrl = server.Url });
+        await using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(server.Url) });
 
         var weakSession = await CreateDroppedSessionAsync(client);
 
@@ -36,7 +36,7 @@ public async Task Dropped_Session_Remains_Rooted_By_Client()
     public async Task Disposed_Session_Is_Removed_From_Client()
     {
         await using var server = await FakeCopilotServer.StartAsync();
-        await using var client = new CopilotClient(new CopilotClientOptions { CliUrl = server.Url });
+        await using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(server.Url) });
 
         var session = await client.CreateSessionAsync(new SessionConfig
         {
@@ -54,7 +54,7 @@ public async Task Disposing_Session_Remains_Rooted_Until_Destroy_Completes()
     {
         await using var server = await FakeCopilotServer.StartAsync();
         server.DelayDestroy();
-        await using var client = new CopilotClient(new CopilotClientOptions { CliUrl = server.Url });
+        await using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(server.Url) });
 
         var session = await client.CreateSessionAsync(new SessionConfig
         {
@@ -77,7 +77,7 @@ public async Task Disposing_Session_Remains_Rooted_Until_Destroy_Completes()
     public async Task StopAsync_Removes_Rooted_Sessions()
     {
         await using var server = await FakeCopilotServer.StartAsync();
-        await using var client = new CopilotClient(new CopilotClientOptions { CliUrl = server.Url });
+        await using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(server.Url) });
 
         _ = await client.CreateSessionAsync(new SessionConfig
         {
@@ -95,7 +95,7 @@ public async Task StopAsync_Keeps_Session_Rooted_Until_Destroy_Completes()
     {
         await using var server = await FakeCopilotServer.StartAsync();
         server.DelayDestroy();
-        await using var client = new CopilotClient(new CopilotClientOptions { CliUrl = server.Url });
+        await using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(server.Url) });
 
         _ = await client.CreateSessionAsync(new SessionConfig
         {
@@ -118,7 +118,7 @@ public async Task StopAsync_Keeps_Session_Rooted_Until_Destroy_Completes()
     public async Task ResumeSessionAsync_Throws_When_Same_Client_Already_Tracks_Session()
     {
         await using var server = await FakeCopilotServer.StartAsync();
-        await using var client = new CopilotClient(new CopilotClientOptions { CliUrl = server.Url });
+        await using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(server.Url) });
 
         var sessionId = "same-session-id";
         await using var session = await client.CreateSessionAsync(new SessionConfig
@@ -140,7 +140,7 @@ public async Task ResumeSessionAsync_Throws_When_Same_Client_Already_Tracks_Sess
     public async Task Generated_Session_Rpc_Throws_When_Session_Disposed()
     {
         await using var server = await FakeCopilotServer.StartAsync();
-        await using var client = new CopilotClient(new CopilotClientOptions { CliUrl = server.Url });
+        await using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(server.Url) });
 
         var session = await client.CreateSessionAsync(new SessionConfig
         {
diff --git a/dotnet/test/Unit/CloneTests.cs b/dotnet/test/Unit/CloneTests.cs
index 0816da9b2..184c13b18 100644
--- a/dotnet/test/Unit/CloneTests.cs
+++ b/dotnet/test/Unit/CloneTests.cs
@@ -1,10 +1,10 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 public class CloneTests
 {
@@ -13,57 +13,39 @@ public void CopilotClientOptions_Clone_CopiesAllProperties()
     {
         var original = new CopilotClientOptions
         {
-            CliPath = "/usr/bin/copilot",
-            CliArgs = ["--verbose", "--debug"],
-            Cwd = "/home/user",
-            Port = 8080,
-            UseStdio = false,
-            CliUrl = "http://localhost:8080",
-            LogLevel = "debug",
-            AutoStart = false,
-
+            Connection = RuntimeConnection.ForTcp(port: 8080, connectionToken: "tok", path: "/usr/bin/copilot", args: ["--verbose", "--debug"]),
+            WorkingDirectory = "/home/user",
+            LogLevel = CopilotLogLevel.Debug,
             Environment = new Dictionary<string, string> { ["KEY"] = "value" },
             GitHubToken = "ghp_test",
             UseLoggedInUser = false,
-            CopilotHome = "/custom/copilot/home",
-            Remote = true,
+            BaseDirectory = "/custom/copilot/home",
+            EnableRemoteSessions = true,
             SessionIdleTimeoutSeconds = 600,
         };
 
         var clone = original.Clone();
 
-        Assert.Equal(original.CliPath, clone.CliPath);
-        Assert.Equal(original.CliArgs, clone.CliArgs);
-        Assert.Equal(original.Cwd, clone.Cwd);
-        Assert.Equal(original.Port, clone.Port);
-        Assert.Equal(original.UseStdio, clone.UseStdio);
-        Assert.Equal(original.CliUrl, clone.CliUrl);
+        Assert.Same(original.Connection, clone.Connection);
+        Assert.Equal(original.WorkingDirectory, clone.WorkingDirectory);
         Assert.Equal(original.LogLevel, clone.LogLevel);
-        Assert.Equal(original.AutoStart, clone.AutoStart);
-
         Assert.Equal(original.Environment, clone.Environment);
         Assert.Equal(original.GitHubToken, clone.GitHubToken);
         Assert.Equal(original.UseLoggedInUser, clone.UseLoggedInUser);
-        Assert.Equal(original.CopilotHome, clone.CopilotHome);
-        Assert.Equal(original.Remote, clone.Remote);
+        Assert.Equal(original.BaseDirectory, clone.BaseDirectory);
+        Assert.Equal(original.EnableRemoteSessions, clone.EnableRemoteSessions);
         Assert.Equal(original.SessionIdleTimeoutSeconds, clone.SessionIdleTimeoutSeconds);
     }
 
     [Fact]
-    public void CopilotClientOptions_Clone_CollectionsAreIndependent()
+    public void CopilotClientOptions_Clone_ConnectionIsShared()
     {
-        var original = new CopilotClientOptions
-        {
-            CliArgs = ["--verbose"],
-        };
+        var connection = RuntimeConnection.ForStdio();
+        var original = new CopilotClientOptions { Connection = connection };
 
         var clone = original.Clone();
 
-        // Mutate clone array
-        clone.CliArgs![0] = "--quiet";
-
-        // Original is unaffected
-        Assert.Equal("--verbose", original.CliArgs![0]);
+        Assert.Same(connection, clone.Connection);
     }
 
     [Fact]
@@ -109,8 +91,8 @@ public void SessionConfig_Clone_CopiesAllProperties()
             SkillDirectories = ["/skills"],
             InstructionDirectories = ["/instructions"],
             DisabledSkills = ["skill1"],
-            OnExitPlanMode = static (_, _) => Task.FromResult(new ExitPlanModeResult()),
-            OnAutoModeSwitch = static (_, _) => Task.FromResult(AutoModeSwitchResponse.No),
+            OnExitPlanModeRequest = static (_, _) => Task.FromResult(new ExitPlanModeResult()),
+            OnAutoModeSwitchRequest = static (_, _) => Task.FromResult(AutoModeSwitchResponse.No),
         };
 
         var clone = original.Clone();
@@ -135,8 +117,8 @@ public void SessionConfig_Clone_CopiesAllProperties()
         Assert.Equal(original.SkillDirectories, clone.SkillDirectories);
         Assert.Equal(original.InstructionDirectories, clone.InstructionDirectories);
         Assert.Equal(original.DisabledSkills, clone.DisabledSkills);
-        Assert.Same(original.OnExitPlanMode, clone.OnExitPlanMode);
-        Assert.Same(original.OnAutoModeSwitch, clone.OnAutoModeSwitch);
+        Assert.Same(original.OnExitPlanModeRequest, clone.OnExitPlanModeRequest);
+        Assert.Same(original.OnAutoModeSwitchRequest, clone.OnAutoModeSwitchRequest);
     }
 
     [Fact]
@@ -315,14 +297,14 @@ public void ResumeSessionConfig_Clone_CopiesModeSwitchHandlers()
     {
         var original = new ResumeSessionConfig
         {
-            OnExitPlanMode = static (_, _) => Task.FromResult(new ExitPlanModeResult()),
-            OnAutoModeSwitch = static (_, _) => Task.FromResult(AutoModeSwitchResponse.No),
+            OnExitPlanModeRequest = static (_, _) => Task.FromResult(new ExitPlanModeResult()),
+            OnAutoModeSwitchRequest = static (_, _) => Task.FromResult(AutoModeSwitchResponse.No),
         };
 
         var clone = original.Clone();
 
-        Assert.Same(original.OnExitPlanMode, clone.OnExitPlanMode);
-        Assert.Same(original.OnAutoModeSwitch, clone.OnAutoModeSwitch);
+        Assert.Same(original.OnExitPlanModeRequest, clone.OnExitPlanModeRequest);
+        Assert.Same(original.OnAutoModeSwitchRequest, clone.OnAutoModeSwitchRequest);
     }
 
     [Fact]
diff --git a/dotnet/test/Unit/CopilotToolTests.cs b/dotnet/test/Unit/CopilotToolTests.cs
index e1cb228fe..76ad0e425 100644
--- a/dotnet/test/Unit/CopilotToolTests.cs
+++ b/dotnet/test/Unit/CopilotToolTests.cs
@@ -7,7 +7,7 @@
 using System.Text.Json;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 public class CopilotToolTests
 {
diff --git a/dotnet/test/Unit/ForwardCompatibilityTests.cs b/dotnet/test/Unit/ForwardCompatibilityTests.cs
index d0265c361..09133dfb5 100644
--- a/dotnet/test/Unit/ForwardCompatibilityTests.cs
+++ b/dotnet/test/Unit/ForwardCompatibilityTests.cs
@@ -6,7 +6,7 @@
 using System.Text.Json.Serialization;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 /// <summary>
 /// Tests for forward-compatible handling of unknown session event types.
@@ -240,7 +240,7 @@ public void RpcEnum_WithNonStringValue_ThrowsJsonException()
     [Fact]
     public void RpcEnum_DefaultValue_HasEmptyStringValue()
     {
-        GitHub.Copilot.SDK.SessionMode mode = default;
+        GitHub.Copilot.SessionMode mode = default;
 
         Assert.Equal(string.Empty, mode.Value);
         Assert.Equal(string.Empty, mode.ToString());
@@ -249,7 +249,7 @@ public void RpcEnum_DefaultValue_HasEmptyStringValue()
     [Fact]
     public void RpcEnum_DefaultValueSerialization_ThrowsJsonException()
     {
-        GitHub.Copilot.SDK.SessionMode mode = default;
+        GitHub.Copilot.SessionMode mode = default;
 
         var exception = Assert.Throws<JsonException>(() => JsonSerializer.Serialize(
             mode,
@@ -304,5 +304,5 @@ public void FromJson_UnknownEventType_PreservesAgentIdNull()
     }
 }
 
-[JsonSerializable(typeof(GitHub.Copilot.SDK.SessionMode))]
+[JsonSerializable(typeof(GitHub.Copilot.SessionMode))]
 internal partial class ForwardCompatibilityJsonContext : JsonSerializerContext;
diff --git a/dotnet/test/Unit/JsonRpcTests.cs b/dotnet/test/Unit/JsonRpcTests.cs
index f4101956f..6c045c8eb 100644
--- a/dotnet/test/Unit/JsonRpcTests.cs
+++ b/dotnet/test/Unit/JsonRpcTests.cs
@@ -7,12 +7,12 @@
 using System.Text.Json.Serialization.Metadata;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 /// <summary>
 /// Behavior tests for the SDK's hand-rolled JSON-RPC transport (params shape, serializer
 /// metadata, request/response routing, error propagation). Reflection is used to force
-/// every generated <c>JsonSerializable</c> registration on the <see cref="GitHub.Copilot.SDK.Rpc.RpcJsonSerializerContext"/>,
+/// every generated <c>JsonSerializable</c> registration on the <see cref="GitHub.Copilot.Rpc.RpcJsonSerializerContext"/>,
 /// which guards against regressions in the C# code generator (<c>scripts/codegen/csharp.ts</c>)
 /// silently dropping a registration. Functional behavior of individual RPC methods lives
 /// in the <c>Rpc*Tests</c> classes; this file owns transport- and serializer-shape concerns.
@@ -160,7 +160,7 @@ public void Dispose()
     private sealed class JsonRpcReflection : IDisposable
     {
         private static readonly Type JsonRpcType =
-            typeof(CopilotClient).Assembly.GetType("GitHub.Copilot.SDK.JsonRpc", throwOnError: true)!;
+            typeof(CopilotClient).Assembly.GetType("GitHub.Copilot.JsonRpc", throwOnError: true)!;
 
         private static readonly JsonSerializerOptions SerializerOptions = new(JsonSerializerDefaults.Web)
         {
diff --git a/dotnet/test/Unit/MSBuildTargetsTests.cs b/dotnet/test/Unit/MSBuildTargetsTests.cs
index 745069ca4..a7d9cc025 100644
--- a/dotnet/test/Unit/MSBuildTargetsTests.cs
+++ b/dotnet/test/Unit/MSBuildTargetsTests.cs
@@ -7,7 +7,7 @@
 using System.Text;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 /// <summary>
 /// Integration tests for the MSBuild targets shipped in
diff --git a/dotnet/test/Unit/PermissionRequestResultKindTests.cs b/dotnet/test/Unit/PermissionRequestResultKindTests.cs
index 67c9eeb41..ce828e6ef 100644
--- a/dotnet/test/Unit/PermissionRequestResultKindTests.cs
+++ b/dotnet/test/Unit/PermissionRequestResultKindTests.cs
@@ -5,7 +5,7 @@
 using System.Text.Json;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 public class PermissionRequestResultKindTests
 {
@@ -21,13 +21,6 @@ public void WellKnownKinds_HaveExpectedValues()
         Assert.Equal("reject", PermissionRequestResultKind.Rejected.Value);
         Assert.Equal("user-not-available", PermissionRequestResultKind.UserNotAvailable.Value);
         Assert.Equal("no-result", PermissionRequestResultKind.NoResult.Value);
-
-        // Deprecated aliases still resolve
-#pragma warning disable CS0618
-        Assert.Equal(PermissionRequestResultKind.Rejected, PermissionRequestResultKind.DeniedInteractivelyByUser);
-        Assert.Equal(PermissionRequestResultKind.UserNotAvailable, PermissionRequestResultKind.DeniedCouldNotRequestFromUser);
-        Assert.Equal(PermissionRequestResultKind.UserNotAvailable, PermissionRequestResultKind.DeniedByRules);
-#pragma warning restore CS0618
     }
 
     [Fact]
diff --git a/dotnet/test/Unit/PublicDtoTests.cs b/dotnet/test/Unit/PublicDtoTests.cs
index 76a0d80bf..473c312ba 100644
--- a/dotnet/test/Unit/PublicDtoTests.cs
+++ b/dotnet/test/Unit/PublicDtoTests.cs
@@ -7,7 +7,7 @@
 using System.Text.Json;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 /// <summary>
 /// Reflection-based safety net that exercises the get/set surface of every public DTO in
@@ -29,7 +29,7 @@ public void Public_Dto_Properties_Can_Be_Set_And_Read()
             .GetTypes()
             .Where(type =>
                 type is { IsClass: true, IsAbstract: false, IsPublic: true } &&
-                type.Namespace?.StartsWith("GitHub.Copilot.SDK", StringComparison.Ordinal) == true &&
+                type.Namespace?.StartsWith("GitHub.Copilot", StringComparison.Ordinal) == true &&
                 type.GetConstructor(Type.EmptyTypes) is not null)
             .OrderBy(type => type.FullName, StringComparer.Ordinal);
 
diff --git a/dotnet/test/Unit/SerializationTests.cs b/dotnet/test/Unit/SerializationTests.cs
index 1ca6562f8..c361987dd 100644
--- a/dotnet/test/Unit/SerializationTests.cs
+++ b/dotnet/test/Unit/SerializationTests.cs
@@ -1,4 +1,4 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
@@ -7,9 +7,9 @@
 #if !NET8_0_OR_GREATER
 using System.Runtime.Serialization;
 #endif
-using GitHub.Copilot.SDK.Rpc;
+using GitHub.Copilot.Rpc;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 /// <summary>
 /// Tests for JSON serialization compatibility with the SDK's configured options.
@@ -26,7 +26,7 @@ public void ProviderConfig_CanSerializeHeaders_WithSdkOptions()
             Headers = new Dictionary<string, string> { ["Authorization"] = "Bearer provider-token" },
             ModelId = "gpt-4o",
             WireModel = "my-finetune-v3",
-            MaxInputTokens = 100_000,
+            MaxPromptTokens = 100_000,
             MaxOutputTokens = 4096
         };
 
@@ -46,7 +46,7 @@ public void ProviderConfig_CanSerializeHeaders_WithSdkOptions()
         Assert.Equal("Bearer provider-token", deserialized.Headers!["Authorization"]);
         Assert.Equal("gpt-4o", deserialized.ModelId);
         Assert.Equal("my-finetune-v3", deserialized.WireModel);
-        Assert.Equal(100_000, deserialized.MaxInputTokens);
+        Assert.Equal(100_000, deserialized.MaxPromptTokens);
         Assert.Equal(4096, deserialized.MaxOutputTokens);
     }
 
@@ -265,7 +265,7 @@ public void McpHttpServerConfig_CanSerializeOauthOptions_WithSdkOptions()
         Assert.Equal("client-id", httpConfig.OauthClientId);
         Assert.False(httpConfig.OauthPublicClient);
         Assert.Equal(McpHttpServerConfigOauthGrantType.ClientCredentials, httpConfig.OauthGrantType);
-        Assert.Equal("*", Assert.Single(httpConfig.Tools));
+        Assert.Equal("*", Assert.Single(httpConfig.Tools!));
         Assert.Equal(3000, httpConfig.Timeout);
     }
 
diff --git a/dotnet/test/Unit/SessionEventSerializationTests.cs b/dotnet/test/Unit/SessionEventSerializationTests.cs
index 3622821dc..3e6d4661f 100644
--- a/dotnet/test/Unit/SessionEventSerializationTests.cs
+++ b/dotnet/test/Unit/SessionEventSerializationTests.cs
@@ -5,7 +5,7 @@
 using System.Text.Json;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 public class SessionEventSerializationTests
 {
diff --git a/dotnet/test/Unit/TelemetryTests.cs b/dotnet/test/Unit/TelemetryTests.cs
index 1a2fdc6e5..9229285b9 100644
--- a/dotnet/test/Unit/TelemetryTests.cs
+++ b/dotnet/test/Unit/TelemetryTests.cs
@@ -6,7 +6,7 @@
 using System.Reflection;
 using Xunit;
 
-namespace GitHub.Copilot.SDK.Test.Unit;
+namespace GitHub.Copilot.Test.Unit;
 
 public class TelemetryTests
 {
@@ -91,7 +91,7 @@ public void TelemetryHelpers_Restores_W3C_Trace_Context()
 
     private static T InvokeTelemetryHelper<T>(string name, params object?[] args)
     {
-        var helperType = typeof(CopilotClient).Assembly.GetType("GitHub.Copilot.SDK.TelemetryHelpers", throwOnError: true)!;
+        var helperType = typeof(CopilotClient).Assembly.GetType("GitHub.Copilot.TelemetryHelpers", throwOnError: true)!;
         var method = helperType.GetMethod(name, BindingFlags.Static | BindingFlags.NonPublic)!;
         return (T)method.Invoke(null, args)!;
     }
diff --git a/scripts/codegen/csharp.ts b/scripts/codegen/csharp.ts
index 8fd6b6f58..f35c0a52b 100644
--- a/scripts/codegen/csharp.ts
+++ b/scripts/codegen/csharp.ts
@@ -569,12 +569,12 @@ function getOrCreateEnum(
     lines.push(`        /// <inheritdoc />`);
     lines.push(`        public override ${enumName} Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)`);
     lines.push(`        {`);
-    lines.push(`            return new(GitHub.Copilot.SDK.GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));`);
+    lines.push(`            return new(GeneratedStringEnumJson.ReadValue(ref reader, typeToConvert));`);
     lines.push(`        }`, "");
     lines.push(`        /// <inheritdoc />`);
     lines.push(`        public override void Write(Utf8JsonWriter writer, ${enumName} value, JsonSerializerOptions options)`);
     lines.push(`        {`);
-    lines.push(`            GitHub.Copilot.SDK.GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(${enumName}));`);
+    lines.push(`            GeneratedStringEnumJson.WriteValue(writer, value.Value, typeof(${enumName}));`);
     lines.push(`        }`);
     lines.push(`    }`);
     lines.push(`}`, "");
@@ -1283,7 +1283,7 @@ using System.Diagnostics.CodeAnalysis;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 
-namespace GitHub.Copilot.SDK;
+namespace GitHub.Copilot;
 `);
 
     // Base class with XML doc
@@ -2243,7 +2243,7 @@ using System.Text.Json;
 using System.Text.Json.Serialization;
 using System.Threading;
 
-namespace GitHub.Copilot.SDK.Rpc;
+namespace GitHub.Copilot.Rpc;
 `);
 
     for (const cls of classes) if (cls) lines.push(cls, "");
@@ -2264,7 +2264,7 @@ namespace GitHub.Copilot.SDK.Rpc;
             if (schemaFile !== "session-events.schema.json") continue;
             for (const name of [...names].sort()) {
                 const typeName = typeToClassName(name);
-                lines.push(`[JsonSerializable(typeof(GitHub.Copilot.SDK.${typeName}), TypeInfoPropertyName = "SessionEvents${typeName}")]`);
+                lines.push(`[JsonSerializable(typeof(GitHub.Copilot.${typeName}), TypeInfoPropertyName = "SessionEvents${typeName}")]`);
             }
         }
         for (const t of typeNames) lines.push(`[JsonSerializable(typeof(${t}))]`);
diff --git a/scripts/docs-validation/extract.ts b/scripts/docs-validation/extract.ts
index 879873048..0b0879db1 100644
--- a/scripts/docs-validation/extract.ts
+++ b/scripts/docs-validation/extract.ts
@@ -302,8 +302,8 @@ function wrapCodeForValidation(block: CodeBlock): string {
       }
 
       // Always ensure SDK using is present
-      if (!usings.some(u => u.includes("GitHub.Copilot.SDK"))) {
-        usings.push("using GitHub.Copilot.SDK;");
+      if (!usings.some(u => u.includes("GitHub.Copilot"))) {
+        usings.push("using GitHub.Copilot;");
       }
 
       // Generate a unique class name based on block location
@@ -336,8 +336,8 @@ ${indentedCode}
       }
     } else {
       // Has structure, but may still need using directive
-      if (!code.includes("using GitHub.Copilot.SDK;")) {
-        code = "using GitHub.Copilot.SDK;\n" + code;
+      if (!code.includes("using GitHub.Copilot;")) {
+        code = "using GitHub.Copilot;\n" + code;
       }
     }
   }
diff --git a/test/scenarios/auth/byok-anthropic/csharp/Program.cs b/test/scenarios/auth/byok-anthropic/csharp/Program.cs
index 6bb9dd231..f29cfd4d8 100644
--- a/test/scenarios/auth/byok-anthropic/csharp/Program.cs
+++ b/test/scenarios/auth/byok-anthropic/csharp/Program.cs
@@ -1,4 +1,4 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var apiKey = Environment.GetEnvironmentVariable("ANTHROPIC_API_KEY");
 var model = Environment.GetEnvironmentVariable("ANTHROPIC_MODEL") ?? "claude-sonnet-4-20250514";
@@ -12,7 +12,7 @@
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
 });
 
 await client.StartAsync();
diff --git a/test/scenarios/auth/byok-azure/csharp/Program.cs b/test/scenarios/auth/byok-azure/csharp/Program.cs
index e6b2789a1..64132bbff 100644
--- a/test/scenarios/auth/byok-azure/csharp/Program.cs
+++ b/test/scenarios/auth/byok-azure/csharp/Program.cs
@@ -1,4 +1,4 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var endpoint = Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT");
 var apiKey = Environment.GetEnvironmentVariable("AZURE_OPENAI_API_KEY");
@@ -13,7 +13,7 @@
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
 });
 
 await client.StartAsync();
diff --git a/test/scenarios/auth/byok-ollama/csharp/Program.cs b/test/scenarios/auth/byok-ollama/csharp/Program.cs
index 585157b66..69578a378 100644
--- a/test/scenarios/auth/byok-ollama/csharp/Program.cs
+++ b/test/scenarios/auth/byok-ollama/csharp/Program.cs
@@ -1,4 +1,4 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var baseUrl = Environment.GetEnvironmentVariable("OLLAMA_BASE_URL") ?? "http://localhost:11434/v1";
 var model = Environment.GetEnvironmentVariable("OLLAMA_MODEL") ?? "llama3.2:3b";
@@ -8,7 +8,7 @@
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
 });
 
 await client.StartAsync();
diff --git a/test/scenarios/auth/byok-openai/csharp/Program.cs b/test/scenarios/auth/byok-openai/csharp/Program.cs
index 5d549bd5c..d98cffbc3 100644
--- a/test/scenarios/auth/byok-openai/csharp/Program.cs
+++ b/test/scenarios/auth/byok-openai/csharp/Program.cs
@@ -1,4 +1,4 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var apiKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY");
 var model = Environment.GetEnvironmentVariable("OPENAI_MODEL") ?? "claude-haiku-4.5";
@@ -12,7 +12,7 @@
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
 });
 
 await client.StartAsync();
diff --git a/test/scenarios/auth/gh-app/csharp/Program.cs b/test/scenarios/auth/gh-app/csharp/Program.cs
index 1f2e27ccf..5933ec087 100644
--- a/test/scenarios/auth/gh-app/csharp/Program.cs
+++ b/test/scenarios/auth/gh-app/csharp/Program.cs
@@ -1,6 +1,6 @@
 using System.Net.Http.Json;
 using System.Text.Json;
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 // GitHub OAuth Device Flow
 var clientId = Environment.GetEnvironmentVariable("GITHUB_OAUTH_CLIENT_ID")
@@ -60,7 +60,7 @@
 // Step 4: Use the token with Copilot
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = accessToken,
 });
 
diff --git a/test/scenarios/bundling/app-backend-to-server/csharp/Program.cs b/test/scenarios/bundling/app-backend-to-server/csharp/Program.cs
index df3a335b0..f6e993f0c 100644
--- a/test/scenarios/bundling/app-backend-to-server/csharp/Program.cs
+++ b/test/scenarios/bundling/app-backend-to-server/csharp/Program.cs
@@ -1,5 +1,5 @@
 using System.Text.Json;
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var port = Environment.GetEnvironmentVariable("PORT") ?? "8080";
 var cliUrl = Environment.GetEnvironmentVariable("CLI_URL")
@@ -21,7 +21,7 @@
         return;
     }
 
-    using var client = new CopilotClient(new CopilotClientOptions { CliUrl = cliUrl });
+    using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl) });
     await client.StartAsync();
 
     try
diff --git a/test/scenarios/bundling/app-direct-server/csharp/Program.cs b/test/scenarios/bundling/app-direct-server/csharp/Program.cs
index 6dd14e9db..c7b9fec70 100644
--- a/test/scenarios/bundling/app-direct-server/csharp/Program.cs
+++ b/test/scenarios/bundling/app-direct-server/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var cliUrl = Environment.GetEnvironmentVariable("COPILOT_CLI_URL") ?? "localhost:3000";
 
-using var client = new CopilotClient(new CopilotClientOptions { CliUrl = cliUrl });
+using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl) });
 await client.StartAsync();
 
 try
diff --git a/test/scenarios/bundling/container-proxy/csharp/Program.cs b/test/scenarios/bundling/container-proxy/csharp/Program.cs
index 6dd14e9db..c7b9fec70 100644
--- a/test/scenarios/bundling/container-proxy/csharp/Program.cs
+++ b/test/scenarios/bundling/container-proxy/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var cliUrl = Environment.GetEnvironmentVariable("COPILOT_CLI_URL") ?? "localhost:3000";
 
-using var client = new CopilotClient(new CopilotClientOptions { CliUrl = cliUrl });
+using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl) });
 await client.StartAsync();
 
 try
diff --git a/test/scenarios/bundling/fully-bundled/csharp/Program.cs b/test/scenarios/bundling/fully-bundled/csharp/Program.cs
index cb67c903c..e9dfbcccc 100644
--- a/test/scenarios/bundling/fully-bundled/csharp/Program.cs
+++ b/test/scenarios/bundling/fully-bundled/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/callbacks/hooks/csharp/Program.cs b/test/scenarios/callbacks/hooks/csharp/Program.cs
index 63c15128f..78184df2a 100644
--- a/test/scenarios/callbacks/hooks/csharp/Program.cs
+++ b/test/scenarios/callbacks/hooks/csharp/Program.cs
@@ -1,10 +1,10 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var hookLog = new List<string>();
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/callbacks/permissions/csharp/Program.cs b/test/scenarios/callbacks/permissions/csharp/Program.cs
index 889eeaff1..cf3275e56 100644
--- a/test/scenarios/callbacks/permissions/csharp/Program.cs
+++ b/test/scenarios/callbacks/permissions/csharp/Program.cs
@@ -1,10 +1,10 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var permissionLog = new List<string>();
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/callbacks/user-input/csharp/Program.cs b/test/scenarios/callbacks/user-input/csharp/Program.cs
index 6ad0454d7..e9fe06968 100644
--- a/test/scenarios/callbacks/user-input/csharp/Program.cs
+++ b/test/scenarios/callbacks/user-input/csharp/Program.cs
@@ -1,10 +1,10 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var inputLog = new List<string>();
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/modes/default/csharp/Program.cs b/test/scenarios/modes/default/csharp/Program.cs
index 243fcb922..23d6c63f0 100644
--- a/test/scenarios/modes/default/csharp/Program.cs
+++ b/test/scenarios/modes/default/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/modes/minimal/csharp/Program.cs b/test/scenarios/modes/minimal/csharp/Program.cs
index 94cbc2034..70081b58d 100644
--- a/test/scenarios/modes/minimal/csharp/Program.cs
+++ b/test/scenarios/modes/minimal/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/prompts/attachments/csharp/Program.cs b/test/scenarios/prompts/attachments/csharp/Program.cs
index 272c89aab..7cafcb86d 100644
--- a/test/scenarios/prompts/attachments/csharp/Program.cs
+++ b/test/scenarios/prompts/attachments/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/prompts/reasoning-effort/csharp/Program.cs b/test/scenarios/prompts/reasoning-effort/csharp/Program.cs
index 719650880..2ed2ae94d 100644
--- a/test/scenarios/prompts/reasoning-effort/csharp/Program.cs
+++ b/test/scenarios/prompts/reasoning-effort/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/prompts/system-message/csharp/Program.cs b/test/scenarios/prompts/system-message/csharp/Program.cs
index 5f22cb029..48afdd7ba 100644
--- a/test/scenarios/prompts/system-message/csharp/Program.cs
+++ b/test/scenarios/prompts/system-message/csharp/Program.cs
@@ -1,10 +1,10 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var piratePrompt = "You are a pirate. Always respond in pirate speak. Say 'Arrr!' in every response. Use nautical terms and pirate slang throughout.";
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/sessions/concurrent-sessions/csharp/Program.cs b/test/scenarios/sessions/concurrent-sessions/csharp/Program.cs
index 142bcb268..a5ba2577b 100644
--- a/test/scenarios/sessions/concurrent-sessions/csharp/Program.cs
+++ b/test/scenarios/sessions/concurrent-sessions/csharp/Program.cs
@@ -1,11 +1,11 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 const string PiratePrompt = "You are a pirate. Always say Arrr!";
 const string RobotPrompt = "You are a robot. Always say BEEP BOOP!";
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/sessions/infinite-sessions/csharp/Program.cs b/test/scenarios/sessions/infinite-sessions/csharp/Program.cs
index fe281292d..2619f25b4 100644
--- a/test/scenarios/sessions/infinite-sessions/csharp/Program.cs
+++ b/test/scenarios/sessions/infinite-sessions/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/sessions/session-resume/csharp/Program.cs b/test/scenarios/sessions/session-resume/csharp/Program.cs
index 73979669d..a1bd015bd 100644
--- a/test/scenarios/sessions/session-resume/csharp/Program.cs
+++ b/test/scenarios/sessions/session-resume/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/sessions/streaming/csharp/Program.cs b/test/scenarios/sessions/streaming/csharp/Program.cs
index 01683df76..518d4b227 100644
--- a/test/scenarios/sessions/streaming/csharp/Program.cs
+++ b/test/scenarios/sessions/streaming/csharp/Program.cs
@@ -1,4 +1,4 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var options = new CopilotClientOptions
 {
@@ -8,7 +8,7 @@
 var cliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH");
 if (!string.IsNullOrEmpty(cliPath))
 {
-    options.CliPath = cliPath;
+    options.Connection = RuntimeConnection.ForStdio(path: cliPath);
 }
 
 using var client = new CopilotClient(options);
@@ -24,7 +24,7 @@
     });
 
     var chunkCount = 0;
-    using var subscription = session.On(evt =>
+    using var subscription = session.On<SessionEvent>(evt =>
     {
         if (evt is AssistantMessageDeltaEvent)
         {
diff --git a/test/scenarios/tools/custom-agents/csharp/Program.cs b/test/scenarios/tools/custom-agents/csharp/Program.cs
index d3c068ade..6c5b980cc 100644
--- a/test/scenarios/tools/custom-agents/csharp/Program.cs
+++ b/test/scenarios/tools/custom-agents/csharp/Program.cs
@@ -1,11 +1,11 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Extensions.AI;
 
 var cliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH");
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = cliPath,
+    Connection = RuntimeConnection.ForStdio(path: cliPath),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/tools/mcp-servers/csharp/Program.cs b/test/scenarios/tools/mcp-servers/csharp/Program.cs
index e3c1ed428..ed667825f 100644
--- a/test/scenarios/tools/mcp-servers/csharp/Program.cs
+++ b/test/scenarios/tools/mcp-servers/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/tools/no-tools/csharp/Program.cs b/test/scenarios/tools/no-tools/csharp/Program.cs
index c3de1de53..a0ea0eefe 100644
--- a/test/scenarios/tools/no-tools/csharp/Program.cs
+++ b/test/scenarios/tools/no-tools/csharp/Program.cs
@@ -1,4 +1,4 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 const string SystemPrompt = """
     You are a minimal assistant with no tools available.
@@ -9,7 +9,7 @@ You can only respond with text based on your training data.
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/tools/skills/csharp/Program.cs b/test/scenarios/tools/skills/csharp/Program.cs
index d0394a396..81adf96a5 100644
--- a/test/scenarios/tools/skills/csharp/Program.cs
+++ b/test/scenarios/tools/skills/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/tools/tool-filtering/csharp/Program.cs b/test/scenarios/tools/tool-filtering/csharp/Program.cs
index f21482b1b..72431c005 100644
--- a/test/scenarios/tools/tool-filtering/csharp/Program.cs
+++ b/test/scenarios/tools/tool-filtering/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/tools/tool-overrides/csharp/Program.cs b/test/scenarios/tools/tool-overrides/csharp/Program.cs
index be8c07ec8..a8c7679de 100644
--- a/test/scenarios/tools/tool-overrides/csharp/Program.cs
+++ b/test/scenarios/tools/tool-overrides/csharp/Program.cs
@@ -1,10 +1,10 @@
 using System.ComponentModel;
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Extensions.AI;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/tools/virtual-filesystem/csharp/Program.cs b/test/scenarios/tools/virtual-filesystem/csharp/Program.cs
index d67a3738c..93ad41f1e 100644
--- a/test/scenarios/tools/virtual-filesystem/csharp/Program.cs
+++ b/test/scenarios/tools/virtual-filesystem/csharp/Program.cs
@@ -1,5 +1,5 @@
 using System.ComponentModel;
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 using Microsoft.Extensions.AI;
 
 // In-memory virtual filesystem
@@ -7,7 +7,7 @@
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/transport/reconnect/csharp/Program.cs b/test/scenarios/transport/reconnect/csharp/Program.cs
index 80dc482da..99e9b91dd 100644
--- a/test/scenarios/transport/reconnect/csharp/Program.cs
+++ b/test/scenarios/transport/reconnect/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var cliUrl = Environment.GetEnvironmentVariable("COPILOT_CLI_URL") ?? "localhost:3000";
 
-using var client = new CopilotClient(new CopilotClientOptions { CliUrl = cliUrl });
+using var client = new CopilotClient(new CopilotClientOptions { Connection = RuntimeConnection.ForUri(cliUrl) });
 await client.StartAsync();
 
 try
diff --git a/test/scenarios/transport/stdio/csharp/Program.cs b/test/scenarios/transport/stdio/csharp/Program.cs
index cb67c903c..e9dfbcccc 100644
--- a/test/scenarios/transport/stdio/csharp/Program.cs
+++ b/test/scenarios/transport/stdio/csharp/Program.cs
@@ -1,8 +1,8 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliPath = Environment.GetEnvironmentVariable("COPILOT_CLI_PATH"),
+    Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
     GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
diff --git a/test/scenarios/transport/tcp/csharp/Program.cs b/test/scenarios/transport/tcp/csharp/Program.cs
index 051c877d2..9fe2b176b 100644
--- a/test/scenarios/transport/tcp/csharp/Program.cs
+++ b/test/scenarios/transport/tcp/csharp/Program.cs
@@ -1,10 +1,10 @@
-using GitHub.Copilot.SDK;
+using GitHub.Copilot;
 
 var cliUrl = Environment.GetEnvironmentVariable("COPILOT_CLI_URL") ?? "localhost:3000";
 
 using var client = new CopilotClient(new CopilotClientOptions
 {
-    CliUrl = cliUrl,
+    Connection = RuntimeConnection.ForUri(cliUrl),
 });
 
 await client.StartAsync();