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

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

@@ -69,6 +69,15 @@ 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

@@ -210,7 +210,7 @@ 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 +236,24 @@ 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, {