fix(acp): stream subagent text chunks (with thoughts)

Propagate `thought` metadata through SubAgent STREAM_TEXT events and render them as agent message/thought chunks in ACP sessions.

packages/cli/src/acp-integration/session/SubAgentTracker.test.ts

@@ -14,6 +14,7 @@ import type {
   SubAgentToolCallEvent,
   SubAgentToolResultEvent,
   SubAgentApprovalRequestEvent,
+  SubAgentStreamTextEvent,
   ToolEditConfirmationDetails,
   ToolInfoConfirmationDetails,
 } from '@qwen-code/qwen-code-core';
@@ -101,6 +102,18 @@ function createInfoConfirmation(
   };
 }
 
+// Helper to create a mock SubAgentStreamTextEvent with required fields
+function createStreamTextEvent(
+  overrides: Partial<SubAgentStreamTextEvent> & { text: string },
+): SubAgentStreamTextEvent {
+  return {
+    subagentId: 'test-subagent',
+    round: 1,
+    timestamp: Date.now(),
+    ...overrides,
+  };
+}
+
 describe('SubAgentTracker', () => {
   let mockContext: SessionContext;
   let mockClient: acp.Client;
@@ -162,6 +175,10 @@ describe('SubAgentTracker', () => {
         SubAgentEventType.TOOL_WAITING_APPROVAL,
         expect.any(Function),
       );
+      expect(onSpy).toHaveBeenCalledWith(
+        SubAgentEventType.STREAM_TEXT,
+        expect.any(Function),
+      );
     });
 
     it('should remove event listeners on cleanup', () => {
@@ -182,6 +199,10 @@ describe('SubAgentTracker', () => {
         SubAgentEventType.TOOL_WAITING_APPROVAL,
         expect.any(Function),
       );
+      expect(offSpy).toHaveBeenCalledWith(
+        SubAgentEventType.STREAM_TEXT,
+        expect.any(Function),
+      );
     });
   });
 
@@ -522,4 +543,163 @@ describe('SubAgentTracker', () => {
       );
     });
   });
+
+  describe('stream text handling', () => {
+    it('should emit agent_message_chunk on STREAM_TEXT event', async () => {
+      tracker.setup(eventEmitter, abortController.signal);
+
+      const event = createStreamTextEvent({
+        text: 'Hello, this is a response from the model.',
+      });
+
+      eventEmitter.emit(SubAgentEventType.STREAM_TEXT, event);
+
+      await vi.waitFor(() => {
+        expect(sendUpdateSpy).toHaveBeenCalled();
+      });
+
+      expect(sendUpdateSpy).toHaveBeenCalledWith(
+        expect.objectContaining({
+          sessionUpdate: 'agent_message_chunk',
+          content: {
+            type: 'text',
+            text: 'Hello, this is a response from the model.',
+          },
+        }),
+      );
+    });
+
+    it('should emit multiple chunks for multiple STREAM_TEXT events', async () => {
+      tracker.setup(eventEmitter, abortController.signal);
+
+      eventEmitter.emit(
+        SubAgentEventType.STREAM_TEXT,
+        createStreamTextEvent({ text: 'First chunk ' }),
+      );
+      eventEmitter.emit(
+        SubAgentEventType.STREAM_TEXT,
+        createStreamTextEvent({ text: 'Second chunk ' }),
+      );
+      eventEmitter.emit(
+        SubAgentEventType.STREAM_TEXT,
+        createStreamTextEvent({ text: 'Third chunk' }),
+      );
+
+      await vi.waitFor(() => {
+        expect(sendUpdateSpy).toHaveBeenCalledTimes(3);
+      });
+
+      expect(sendUpdateSpy).toHaveBeenNthCalledWith(
+        1,
+        expect.objectContaining({
+          sessionUpdate: 'agent_message_chunk',
+          content: { type: 'text', text: 'First chunk ' },
+        }),
+      );
+      expect(sendUpdateSpy).toHaveBeenNthCalledWith(
+        2,
+        expect.objectContaining({
+          sessionUpdate: 'agent_message_chunk',
+          content: { type: 'text', text: 'Second chunk ' },
+        }),
+      );
+      expect(sendUpdateSpy).toHaveBeenNthCalledWith(
+        3,
+        expect.objectContaining({
+          sessionUpdate: 'agent_message_chunk',
+          content: { type: 'text', text: 'Third chunk' },
+        }),
+      );
+    });
+
+    it('should not emit when aborted', async () => {
+      tracker.setup(eventEmitter, abortController.signal);
+      abortController.abort();
+
+      const event = createStreamTextEvent({
+        text: 'This should not be emitted',
+      });
+
+      eventEmitter.emit(SubAgentEventType.STREAM_TEXT, event);
+
+      await new Promise((resolve) => setTimeout(resolve, 10));
+
+      expect(sendUpdateSpy).not.toHaveBeenCalled();
+    });
+
+    it('should emit agent_thought_chunk when thought flag is true', async () => {
+      tracker.setup(eventEmitter, abortController.signal);
+
+      const event = createStreamTextEvent({
+        text: 'Let me think about this...',
+        thought: true,
+      });
+
+      eventEmitter.emit(SubAgentEventType.STREAM_TEXT, event);
+
+      await vi.waitFor(() => {
+        expect(sendUpdateSpy).toHaveBeenCalled();
+      });
+
+      expect(sendUpdateSpy).toHaveBeenCalledWith(
+        expect.objectContaining({
+          sessionUpdate: 'agent_thought_chunk',
+          content: {
+            type: 'text',
+            text: 'Let me think about this...',
+          },
+        }),
+      );
+    });
+
+    it('should emit agent_message_chunk when thought flag is false', async () => {
+      tracker.setup(eventEmitter, abortController.signal);
+
+      const event = createStreamTextEvent({
+        text: 'Here is the answer.',
+        thought: false,
+      });
+
+      eventEmitter.emit(SubAgentEventType.STREAM_TEXT, event);
+
+      await vi.waitFor(() => {
+        expect(sendUpdateSpy).toHaveBeenCalled();
+      });
+
+      expect(sendUpdateSpy).toHaveBeenCalledWith(
+        expect.objectContaining({
+          sessionUpdate: 'agent_message_chunk',
+          content: {
+            type: 'text',
+            text: 'Here is the answer.',
+          },
+        }),
+      );
+    });
+
+    it('should emit agent_message_chunk when thought flag is undefined', async () => {
+      tracker.setup(eventEmitter, abortController.signal);
+
+      // Event without thought flag (undefined)
+      const event = createStreamTextEvent({
+        text: 'Default behavior text.',
+      });
+
+      eventEmitter.emit(SubAgentEventType.STREAM_TEXT, event);
+
+      await vi.waitFor(() => {
+        expect(sendUpdateSpy).toHaveBeenCalled();
+      });
+
+      expect(sendUpdateSpy).toHaveBeenCalledWith(
+        expect.objectContaining({
+          sessionUpdate: 'agent_message_chunk',
+          content: {
+            type: 'text',
+            text: 'Default behavior text.',
+          },
+        }),
+      );
+    });
+  });
 });