Coding Agent Explorer

A real-time .NET proxy and dashboard for inspecting Claude Code API calls. Intercept, visualize, and analyze every request and response between Claude Code and the Anthropic API.

With Coding Agent Explorer, you can:

See every API request and response between Claude Code and the Anthropic API in real time
Inspect full request/response headers, bodies, and streaming SSE events
Track token usage, model selection, and time-to-first-token
Follow the conversation as a readable chat-style timeline
Capture and inspect MCP tool calls between Claude Code and HTTP-based MCP servers
Monitor Claude Code hook events alongside API traffic

Dashboard

The dashboard offers three views for inspecting your coding agent's activity: HTTP Inspector, Conversation View, and MCP Observer.

HTTP Inspector

Every API request and response is captured and displayed in a table with full headers, request and response bodies, streaming SSE events, token usage, and timing details.

Conversation View

The Conversation View renders the raw API traffic as a readable chat-style timeline, showing messages, tool calls, responses, and hook events in the order they occurred.

MCP Observer

The MCP Observer acts as a proxy between Claude Code and any HTTP-based MCP server. Configure the destination URL and all MCP traffic is captured and displayed in real time. The MCP Observer will be covered in a future blog post.

Prerequisites

.NET 10 SDK or later

Getting Started

1. Install .NET 10 SDK

Download and install the .NET 10 SDK if you do not already have it.

2. Clone the repository

git clone https://github.com/tndata/CodingAgentExplorer.git
cd CodingAgentExplorer

3. Build and run

dotnet build
dotnet run --project CodingAgentExplorer

This starts four endpoints:

Port 8888 - The reverse proxy (HTTP, point your coding agent here)
Port 9999 - The MCP proxy (HTTP, used by the MCP Observer)
Port 5000 - The web dashboard (HTTP)
Port 5001 - The web dashboard (HTTPS, auto-launches in browser)

4. Configure your coding agent

For Claude Code, set the ANTHROPIC_BASE_URL environment variable to point at the proxy.

Linux / macOS:

Use source (not bash) so the variable is exported to your current shell:

source EnableProxy.sh

Run source DisableProxy.sh to clear it when you are done.

Windows (cmd):

EnableProxy.bat

Run DisableProxy.bat to clear it.

Windows (PowerShell):

# Enable
$env:ANTHROPIC_BASE_URL = "http://localhost:8888"

# Disable
Remove-Item Env:ANTHROPIC_BASE_URL

All scripts only affect the current terminal session. The variable is not persisted, so closing the terminal automatically clears it.

Then use Claude Code as you normally would.

5. Open the dashboard

Navigate to https://localhost:5001 in your browser. On Windows the browser opens automatically on dotnet run. On macOS and Linux, open it manually.

You will see three views:

HTTP Inspector - Table view of all proxied requests with headers, bodies, SSE events, and timing details
Conversation View - Chat-style display showing messages, tool use, and responses
MCP Observer - Dedicated view for inspecting MCP server traffic (see below)

MCP Observer

The MCP Observer lets you intercept and inspect traffic between Claude Code and any Model Context Protocol (MCP) server. It acts as a transparent proxy on port 9999, sitting between Claude Code and the real MCP server.

Claude Code  --►  MCP Observer (port 9999)  --►  Real MCP Server
                         |
                         ▼
                  Dashboard (port 5000/5001)

What it shows

Every MCP request and response in real time, sorted chronologically
The JSON-RPC method for each request (initialize, tools/list, tools/call, etc.)
For tools/call, the specific tool name is shown inline, e.g. tools/call (query-docs)
A Pretty view that renders responses in a readable format per method type:
- tools/list - one card per tool with name, description, and parameters
- initialize - protocol version, server name, and capabilities
- tools/call - the returned content rendered directly
A Raw view with pretty-printed JSON for all other responses
Request and response bodies side by side

Setup

Step 1: Open the MCP Observer at https://localhost:5001/mcp/index.html.

Step 2: Enter the URL of the real MCP server in the destination field and click Set.

Step 3: Register the proxy as an MCP server in Claude Code:

claude mcp add --transport http mcp_proxy http://localhost:9999

Claude Code will now route all MCP traffic through the observer. To remove it later:

claude mcp remove mcp_proxy

Sample MCP services to try

Service	URL	Sample prompt
Microsoft Learn	`https://learn.microsoft.com/api/mcp`	"How do I create an Azure Container App using az cli?"
Context7	`https://mcp.context7.com/mcp`	"How do I set up middleware in Next.js 15? use context7"

Publishing

Run the publish script from the repo root to build release artifacts into Published/ (gitignored). Each script builds both projects for the current platform.

Windows:

publish.bat

Output	Description
`Published\CodingAgentExplorer\`	Proxy + dashboard (exe, wwwroot, appsettings.json)
`Published\HookAgent\HookAgent.exe`	HookAgent (win-x64, single-file)

macOS / Linux:

bash publish.sh

Output	Description
`Published/CodingAgentExplorer/`	Proxy + dashboard (exe, wwwroot, appsettings.json)
`Published/HookAgent/HookAgent`	HookAgent (current platform, single-file)

All outputs require the .NET 10 runtime on the target machine. Add Published/HookAgent to your PATH to use HookAgent as a Claude Code hook command.

HookAgent

HookAgent is a small companion CLI tool that acts as a Claude Code hook command. It bridges Claude Code's hook system and the CodingAgentExplorer dashboard, letting you see every hook event (session start/end, tool calls, permission requests, notifications, and more) appear in the conversation view in real time.

How it works

Claude Code invokes hook commands by writing a JSON payload to stdin and reading the exit code and stdout/stderr on completion. HookAgent:

Reads the JSON payload from stdin
Collects Claude Code environment variables (CLAUDE_PROJECT_DIR, CLAUDE_ENV_FILE, etc.)
POSTs everything to the dashboard at http://localhost:5000/api/hook-event
Relays the server's exitCode, stdout, and stderr back to Claude Code
Exits silently with code 0 if the dashboard is not running, so it never blocks Claude Code

Setup on Windows

Step 1: Run publish.bat to build both projects.

Step 2: Copy Published\HookAgent\ into the working directory where students will run claude. You can also add it to your PATH so the command is available globally.

C:\MyProject\
  HookAgent\
    HookAgent.exe
  .claude\
    settings.json

Step 3: Copy HookAgent\Sample-Settings-Windows\settings.json from the repo to .claude\settings.json in the working directory. This registers HookAgent for all 15 Claude Code hook events.

Step 4: Start CodingAgentExplorer, then run claude from the working directory. Hook events appear in the Conversation View alongside API requests.

Note: Claude Code runs hook commands through bash on Windows too. Always use forward slashes in the command path: HookAgent/HookAgent.exe.

Setup on macOS / Linux

Step 1: Run bash publish.sh to build both projects for your platform.

Step 2: Copy Published/HookAgent/ into the working directory where students will run claude. You can also add it to your PATH so the command is available globally.

~/MyProject/
  HookAgent/
    HookAgent
  .claude/
    settings.json

Step 3: Copy HookAgent/Sample-Settings-LinuxMacOS/settings.json from the repo to .claude/settings.json in the working directory. This registers HookAgent for all 15 Claude Code hook events.

Step 4: Start CodingAgentExplorer, then run claude from the working directory. Hook events appear in the Conversation View alongside API requests.

Verify it works

Test HookAgent manually before starting a Claude Code session:

echo '{"hook_event_name":"UserPromptSubmit","session_id":"test"}' | HookAgent/HookAgent.exe

If the dashboard is running, a UserPromptSubmit event appears in the Conversation View immediately. If the dashboard is not running, the command exits silently with code 0.

Example

Hook events appear inline in the Conversation View, interleaved with API requests in chronological order. Each event shows the event type, timestamp, session, and any stdout returned by the dashboard.

Hook events captured

Event	When it fires
`SessionStart`	Claude Code session begins or resumes
`UserPromptSubmit`	User submits a prompt
`PreToolUse`	Before any tool call executes
`PostToolUse`	After a tool call succeeds
`PostToolUseFailure`	After a tool call fails
`PermissionRequest`	When Claude Code asks for permission
`Stop`	Claude finishes responding
`SubagentStart` / `SubagentStop`	A subagent is spawned or finishes
`Notification`	Claude Code sends a notification
`PreCompact`	Before context compaction
`ConfigChange`	A settings file changes during the session
`TeammateIdle` / `TaskCompleted`	Agent team events
`SessionEnd`	Session terminates

Architecture

  Coding Agent  ──►  CodingAgentExplorer (port 8888)  ──►  LLM API
                            │
                            ▼
                     Web Dashboard (port 5000/5001)
                     Real-time via SignalR

ASP.NET Core with YARP reverse proxy
SignalR for real-time dashboard updates
Vanilla HTML/JS/CSS frontend (no build step required)
Single NuGet dependency (Yarp.ReverseProxy)

Project Structure

├── publish.bat                         # Publishes both projects to Published/ (Windows, win-x64)
├── publish.sh                          # Publishes both projects to Published/ (all platforms)
├── CodingAgentExplorer/
│   ├── Program.cs                      # App setup: YARP, SignalR, dual-port Kestrel
│   ├── Models/                         # DTOs: ProxiedRequest, ClaudeRequestBody, SseEvent, HookEvent
│   ├── Services/RequestStore.cs        # In-memory circular buffer (max 1000 requests)
│   ├── Services/HookEventStore.cs      # In-memory store for hook events
│   ├── Services/McpRequestStore.cs     # In-memory store for MCP requests
│   ├── Services/McpProxyConfig.cs      # Holds the configured MCP destination URL
│   ├── Proxy/CaptureTransformProvider.cs  # YARP ITransformProvider for request/response capture
│   ├── Proxy/DynamicProxyConfigProvider.cs # Dynamic YARP config for Claude (8888) and MCP (9999) routes
│   ├── Hubs/DashboardHub.cs            # SignalR hub for real-time dashboard updates
│   └── wwwroot/                        # Dashboard SPA (vanilla HTML/JS/CSS)
│       ├── index.html                  # Landing page with view selection
│       ├── inspector/                  # HTTP Inspector view
│       ├── conversation/               # Conversation view
│       ├── mcp/                        # MCP Observer view
│       ├── css/                        # Stylesheets
│       └── js/                         # Dashboard and conversation scripts
└── HookAgent/                          # Single-file CLI tool for Claude Code hooks

Security

API keys (x-api-key and Authorization headers) are automatically redacted from stored request data
The proxy only listens on localhost - it is not exposed to the network
Request data is stored in memory only (max 1000 requests, no persistence)

About the author

This tool was developed by Tore Nestenius, a seasoned .NET instructor and consultant with over 25 years of experience in software development and architecture. With extensive expertise in .NET, Azure, and cloud computing, Tore is passionate about helping developers and organizations build robust software solutions and optimize their development processes. A frequent speaker at conferences and user groups, Tore actively shares his knowledge and insights with the community, fostering learning and growth for developers worldwide.

Other Projects by the Author

CloudDebugger - A .NET web application designed to explore and learn about various Azure services and features, including authentication, configuration, networking, and more.

Want to learn more about AI agents?

Coding Agent Explorer was built as a teaching tool for Tore Nestenius' AI agent workshops and presentations, helping developers understand what happens under the hood when AI coding agents work.

Join one of Tore's workshops for programmers at tn-data.se/courses to deepen your understanding of AI coding agents, .NET development, and cloud architecture.

What About Other Coding Agents?

Coding Agent Explorer currently supports Claude Code with the Anthropic API. Support for additional coding agents may be added in the future.

License

This project is licensed under the MIT License.

Name		Name	Last commit message	Last commit date
Latest commit History 50 Commits
.github		.github
CodingAgentExplorer		CodingAgentExplorer
HookAgent		HookAgent
docs/images		docs/images
.editorconfig		.editorconfig
.gitattributes		.gitattributes
.gitignore		.gitignore
CLAUDE.md		CLAUDE.md
CodingAgentExplorer.slnx		CodingAgentExplorer.slnx
DisableProxy.bat		DisableProxy.bat
DisableProxy.sh		DisableProxy.sh
EnableProxy.bat		EnableProxy.bat
EnableProxy.sh		EnableProxy.sh
LICENSE		LICENSE
README.md		README.md
Start- Coding Agent Explorer Web UI.url		Start- Coding Agent Explorer Web UI.url
publish.bat		publish.bat
publish.sh		publish.sh

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Coding Agent Explorer

Dashboard

HTTP Inspector

Conversation View

MCP Observer

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Prerequisites

Getting Started

1. Install .NET 10 SDK

2. Clone the repository

3. Build and run

4. Configure your coding agent

5. Open the dashboard

MCP Observer

What it shows

Setup

Sample MCP services to try

Publishing

HookAgent

How it works

Setup on Windows

Setup on macOS / Linux

Verify it works

Example

Hook events captured

Architecture

Project Structure

Security

About the author

Other Projects by the Author

Want to learn more about AI agents?

What About Other Coding Agents?

License

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