fix(auto-instrumentation): Fix AI SDK streaming version handling for v3/v4+/v5

e2e/scenarios/ai-sdk-instrumentation/assertions.ts

@@ -645,6 +645,7 @@ export function defineAISDKInstrumentationAssertions(options: {
   agentSpanName?: AgentSpanName;
   name: string;
   runScenario: RunAISDKScenario;
+  sdkMajorVersion: number;
   snapshotName: string;
   supportsAttachmentScenario: boolean;
   supportsDenyOutputOverrideScenario: boolean;
@@ -894,6 +895,32 @@ export function defineAISDKInstrumentationAssertions(options: {
       });
     }
 
+    if (options.sdkMajorVersion >= 4) {
+      test(
+        "captures sync streamText()/streamObject() paths in v4+",
+        testConfig,
+        () => {
+          const root = findLatestSpan(events, ROOT_NAME);
+          const streamTrace = findStreamTrace(events);
+
+          expectOperationParentedByRoot(streamTrace.operation, root);
+          expectAISDKParentSpan(streamTrace.parent);
+          expect(operationName(streamTrace.operation)).toBe("stream");
+          expect(streamTrace.parent?.span.name).toBe("streamText");
+
+          if (options.supportsStreamObject) {
+            const streamObjectTrace = findStreamObjectTrace(events);
+            expectOperationParentedByRoot(streamObjectTrace.operation, root);
+            expectAISDKParentSpan(streamObjectTrace.parent);
+            expect(operationName(streamObjectTrace.operation)).toBe(
+              "stream-object",
+            );
+            expect(streamObjectTrace.parent?.span.name).toBe("streamObject");
+          }
+        },
+      );
+    }
+
     if (options.agentSpanName) {
       test("captures trace for agent.generate()", testConfig, () => {
         const root = findLatestSpan(events, ROOT_NAME);
@@ -922,6 +949,18 @@ export function defineAISDKInstrumentationAssertions(options: {
         expect(trace.modelChildren.length).toBeGreaterThanOrEqual(1);
         expect(trace.latestChild?.output).toBeDefined();
       });
+
+      if (options.sdkMajorVersion === 5 && options.agentSpanName === "Agent") {
+        test("captures Agent.stream() path in v5", testConfig, () => {
+          const root = findLatestSpan(events, ROOT_NAME);
+          const trace = findAgentStreamTrace(events, "Agent");
+
+          expectOperationParentedByRoot(trace.operation, root);
+          expectAISDKParentSpan(trace.parent);
+          expect(operationName(trace.operation)).toBe("agent-stream");
+          expect(trace.parent?.span.name).toBe("Agent.stream");
+        });
+      }
     }
 
     if (options.supportsDenyOutputOverrideScenario) {

e2e/scenarios/ai-sdk-instrumentation/scenario.test.ts

@@ -53,6 +53,7 @@ for (const scenario of aiSDKScenarios) {
       supportsOutputObjectScenario,
       supportsStreamObject: scenario.supportsStreamObject,
       supportsToolExecution: scenario.supportsToolExecution,
+      sdkMajorVersion,
       testFileUrl: import.meta.url,
       timeoutMs: AI_SDK_SCENARIO_TIMEOUT_MS,
     });
@@ -76,6 +77,7 @@ for (const scenario of aiSDKScenarios) {
       supportsOutputObjectScenario,
       supportsStreamObject: scenario.supportsStreamObject,
       supportsToolExecution: scenario.supportsToolExecution,
+      sdkMajorVersion,
       testFileUrl: import.meta.url,
       timeoutMs: AI_SDK_SCENARIO_TIMEOUT_MS,
     });

js/src/auto-instrumentations/configs/ai-sdk.ts

@@ -39,19 +39,33 @@ export const aiSDKConfigs: InstrumentationConfig[] = [
     },
   },
 
-  // streamText - function returning stream
+  // streamText - async function (v3 only, before the sync refactor in v4)
   {
     channelName: aiSDKChannels.streamText.channelName,
     module: {
       name: "ai",
-      versionRange: ">=3.0.0",
+      versionRange: ">=3.0.0 <4.0.0",
       filePath: "dist/index.mjs",
     },
     functionQuery: {
       functionName: "streamText",
       kind: "Async",
     },
   },
+
+  // streamText - sync function returning stream (v4+)
+  {
+    channelName: aiSDKChannels.streamTextSync.channelName,
+    module: {
+      name: "ai",
+      versionRange: ">=4.0.0",
+      filePath: "dist/index.mjs",
+    },
+    functionQuery: {
+      functionName: "streamText",
+      kind: "Sync",
+    },
+  },
   {
     channelName: aiSDKChannels.streamText.channelName,
     module: {
@@ -91,19 +105,33 @@ export const aiSDKConfigs: InstrumentationConfig[] = [
     },
   },
 
-  // streamObject - function returning stream
+  // streamObject - async function (v3 only, before the sync refactor in v4)
   {
     channelName: aiSDKChannels.streamObject.channelName,
     module: {
       name: "ai",
-      versionRange: ">=3.0.0",
+      versionRange: ">=3.0.0 <4.0.0",
       filePath: "dist/index.mjs",
     },
     functionQuery: {
       functionName: "streamObject",
       kind: "Async",
     },
   },
+
+  // streamObject - sync function returning stream (v4+)
+  {
+    channelName: aiSDKChannels.streamObjectSync.channelName,
+    module: {
+      name: "ai",
+      versionRange: ">=4.0.0",
+      filePath: "dist/index.mjs",
+    },
+    functionQuery: {
+      functionName: "streamObject",
+      kind: "Sync",
+    },
+  },
   {
     channelName: aiSDKChannels.streamObject.channelName,
     module: {
@@ -147,32 +175,32 @@ export const aiSDKConfigs: InstrumentationConfig[] = [
     },
   },
 
-  // Agent.stream - async method (v5 only)
+  // Agent.stream - sync method (v5 only)
   // The compiled AI SDK bundle emits this as an anonymous class method, so we
-  // target the first async `stream` method in the file instead of a class name.
+  // target the first sync `stream` method in the file instead of a class name.
   {
-    channelName: aiSDKChannels.agentStream.channelName,
+    channelName: aiSDKChannels.agentStreamSync.channelName,
     module: {
       name: "ai",
       versionRange: ">=5.0.0 <6.0.0",
       filePath: "dist/index.mjs",
     },
     functionQuery: {
       methodName: "stream",
-      kind: "Async",
+      kind: "Sync",
       index: 0,
     },
   },
   {
-    channelName: aiSDKChannels.agentStream.channelName,
+    channelName: aiSDKChannels.agentStreamSync.channelName,
     module: {
       name: "ai",
       versionRange: ">=5.0.0 <6.0.0",
       filePath: "dist/index.js",
     },
     functionQuery: {
       methodName: "stream",
-      kind: "Async",
+      kind: "Sync",
       index: 0,
     },
   },

js/src/instrumentation/plugins/ai-sdk-channels.ts

@@ -33,6 +33,15 @@ export const aiSDKChannels = defineChannels("ai", {
     channelName: "streamText",
     kind: "async",
   }),
+  streamTextSync: channel<
+    [AISDKCallParams],
+    AISDKResult,
+    AISDKChannelContext,
+    unknown
+  >({
+    channelName: "streamText.sync",
+    kind: "sync-stream",
+  }),
   generateObject: channel<
     [AISDKCallParams],
     AISDKStreamResult,
@@ -51,6 +60,15 @@ export const aiSDKChannels = defineChannels("ai", {
     channelName: "streamObject",
     kind: "async",
   }),
+  streamObjectSync: channel<
+    [AISDKCallParams],
+    AISDKResult,
+    AISDKChannelContext,
+    unknown
+  >({
+    channelName: "streamObject.sync",
+    kind: "sync-stream",
+  }),
   agentGenerate: channel<
     [AISDKCallParams],
     AISDKStreamResult,
@@ -69,6 +87,15 @@ export const aiSDKChannels = defineChannels("ai", {
     channelName: "Agent.stream",
     kind: "async",
   }),
+  agentStreamSync: channel<
+    [AISDKCallParams],
+    AISDKResult,
+    AISDKChannelContext,
+    unknown
+  >({
+    channelName: "Agent.stream.sync",
+    kind: "sync-stream",
+  }),
   toolLoopAgentGenerate: channel<
     [AISDKCallParams],
     AISDKStreamResult,

js/src/instrumentation/plugins/ai-sdk-plugin.ts

@@ -1,5 +1,9 @@
 import { BasePlugin } from "../core";
-import { traceStreamingChannel, unsubscribeAll } from "../core/channel-tracing";
+import {
+  traceStreamingChannel,
+  traceSyncStreamChannel,
+  unsubscribeAll,
+} from "../core/channel-tracing";
 import { SpanTypeAttribute } from "../../../util/index";
 import { getCurrentUnixTimestamp } from "../../util";
 import { Attachment, type Span, withCurrent } from "../../logger";
@@ -144,6 +148,24 @@ export class AISDKPlugin extends BasePlugin {
       }),
     );
 
+    // streamText - sync function returning stream (v4+, used by auto-hook)
+    this.unsubscribers.push(
+      traceSyncStreamChannel(aiSDKChannels.streamTextSync, {
+        name: "streamText",
+        type: SpanTypeAttribute.LLM,
+        extractInput: ([params], event, span) =>
+          prepareAISDKInput(params, event, span, denyOutputPaths),
+        patchResult: ({ endEvent, result, span, startTime }) =>
+          patchAISDKStreamingResult({
+            defaultDenyOutputPaths: denyOutputPaths,
+            endEvent,
+            result,
+            span,
+            startTime,
+          }),
+      }),
+    );
+
     // generateObject - async function that may return streams
     this.unsubscribers.push(
       traceStreamingChannel(aiSDKChannels.generateObject, {
@@ -190,6 +212,24 @@ export class AISDKPlugin extends BasePlugin {
       }),
     );
 
+    // streamObject - sync function returning stream (v4+, used by auto-hook)
+    this.unsubscribers.push(
+      traceSyncStreamChannel(aiSDKChannels.streamObjectSync, {
+        name: "streamObject",
+        type: SpanTypeAttribute.LLM,
+        extractInput: ([params], event, span) =>
+          prepareAISDKInput(params, event, span, denyOutputPaths),
+        patchResult: ({ endEvent, result, span, startTime }) =>
+          patchAISDKStreamingResult({
+            defaultDenyOutputPaths: denyOutputPaths,
+            endEvent,
+            result,
+            span,
+            startTime,
+          }),
+      }),
+    );
+
     // Agent.generate - async method
     this.unsubscribers.push(
       traceStreamingChannel(aiSDKChannels.agentGenerate, {
@@ -210,7 +250,7 @@ export class AISDKPlugin extends BasePlugin {
       }),
     );
 
-    // Agent.stream - async method returning stream
+    // Agent.stream - async method returning stream (v5, used by wrapAISDK)
     this.unsubscribers.push(
       traceStreamingChannel(aiSDKChannels.agentStream, {
         name: "Agent.stream",
@@ -236,6 +276,24 @@ export class AISDKPlugin extends BasePlugin {
       }),
     );
 
+    // Agent.stream - sync method returning stream (v5, used by auto-hook)
+    this.unsubscribers.push(
+      traceSyncStreamChannel(aiSDKChannels.agentStreamSync, {
+        name: "Agent.stream",
+        type: SpanTypeAttribute.LLM,
+        extractInput: ([params], event, span) =>
+          prepareAISDKInput(params, event, span, denyOutputPaths),
+        patchResult: ({ endEvent, result, span, startTime }) =>
+          patchAISDKStreamingResult({
+            defaultDenyOutputPaths: denyOutputPaths,
+            endEvent,
+            result,
+            span,
+            startTime,
+          }),
+      }),
+    );
+
     // ToolLoopAgent.generate - async method
     this.unsubscribers.push(
       traceStreamingChannel(aiSDKChannels.toolLoopAgentGenerate, {