fix(cli): resolve subagent grouping and UI state persistence (#22252)

packages/core/src/agents/local-invocation.test.ts

@@ -207,8 +207,11 @@ describe('LocalSubagentInvocation', () => {
           ),
         },
       ]);
-      expect(result.returnDisplay).toBe('Analysis complete.');
-      expect(result.returnDisplay).not.toContain('Termination Reason');
+      const display = result.returnDisplay as SubagentProgress;
+      expect(display.isSubagentProgress).toBe(true);
+      expect(display.state).toBe('completed');
+      expect(display.result).toBe('Analysis complete.');
+      expect(display.terminateReason).toBe(AgentTerminateMode.GOAL);
     });
 
     it('should show detailed UI for non-goal terminations (e.g., TIMEOUT)', async () => {
@@ -220,11 +223,11 @@ describe('LocalSubagentInvocation', () => {
 
       const result = await invocation.execute(signal, updateOutput);
 
-      expect(result.returnDisplay).toContain(
-        '### Subagent MockAgent Finished Early',
-      );
-      expect(result.returnDisplay).toContain('**Termination Reason:** TIMEOUT');
-      expect(result.returnDisplay).toContain('Partial progress...');
+      const display = result.returnDisplay as SubagentProgress;
+      expect(display.isSubagentProgress).toBe(true);
+      expect(display.state).toBe('completed');
+      expect(display.result).toBe('Partial progress...');
+      expect(display.terminateReason).toBe(AgentTerminateMode.TIMEOUT);
     });
 
     it('should stream THOUGHT_CHUNK activities from the executor', async () => {
@@ -250,8 +253,8 @@ describe('LocalSubagentInvocation', () => {
 
       await invocation.execute(signal, updateOutput);
 
-      expect(updateOutput).toHaveBeenCalledTimes(3); // Initial + 2 updates
-      const lastCall = updateOutput.mock.calls[2][0] as SubagentProgress;
+      expect(updateOutput).toHaveBeenCalledTimes(4); // Initial + 2 updates + Final completion
+      const lastCall = updateOutput.mock.calls[3][0] as SubagentProgress;
       expect(lastCall.recentActivity).toContainEqual(
         expect.objectContaining({
           type: 'thought',
@@ -283,8 +286,8 @@ describe('LocalSubagentInvocation', () => {
 
       await invocation.execute(signal, updateOutput);
 
-      expect(updateOutput).toHaveBeenCalledTimes(3);
-      const lastCall = updateOutput.mock.calls[2][0] as SubagentProgress;
+      expect(updateOutput).toHaveBeenCalledTimes(4); // Initial + 2 updates + Final completion
+      const lastCall = updateOutput.mock.calls[3][0] as SubagentProgress;
       expect(lastCall.recentActivity).toContainEqual(
         expect.objectContaining({
           type: 'thought',
@@ -312,7 +315,10 @@ describe('LocalSubagentInvocation', () => {
       // Execute without the optional callback
       const result = await invocation.execute(signal);
       expect(result.error).toBeUndefined();
-      expect(result.returnDisplay).toBe('Done');
+      const display = result.returnDisplay as SubagentProgress;
+      expect(display.isSubagentProgress).toBe(true);
+      expect(display.state).toBe('completed');
+      expect(display.result).toBe('Done');
     });
 
     it('should handle executor run failure', async () => {

packages/core/src/agents/local-invocation.ts

@@ -6,7 +6,6 @@
 
 import { type AgentLoopContext } from '../config/agent-loop-context.js';
 import { LocalAgentExecutor } from './local-executor.js';
-import { safeJsonToMarkdown } from '../utils/markdownUtils.js';
 import {
   BaseToolInvocation,
   type ToolResult,
@@ -246,28 +245,27 @@ export class LocalSubagentInvocation extends BaseToolInvocation<
         throw cancelError;
       }
 
-      const displayResult = safeJsonToMarkdown(output.result);
+      const progress: SubagentProgress = {
+        isSubagentProgress: true,
+        agentName: this.definition.name,
+        recentActivity: [...recentActivity],
+        state: 'completed',
+        result: output.result,
+        terminateReason: output.terminate_reason,
+      };
+
+      if (updateOutput) {
+        updateOutput(progress);
+      }
 
       const resultContent = `Subagent '${this.definition.name}' finished.
 Termination Reason: ${output.terminate_reason}
 Result:
 ${output.result}`;
 
-      const displayContent =
-        output.terminate_reason === AgentTerminateMode.GOAL
-          ? displayResult
-          : `
-### Subagent ${this.definition.name} Finished Early
-
-**Termination Reason:** ${output.terminate_reason}
-
-**Result/Summary:**
-${displayResult}
-`;
-
       return {
         llmContent: [{ text: resultContent }],
-        returnDisplay: displayContent,
+        returnDisplay: progress,
       };
     } catch (error) {
       const errorMessage =

packages/core/src/agents/types.ts

@@ -87,6 +87,8 @@ export interface SubagentProgress {
   agentName: string;
   recentActivity: SubagentActivityItem[];
   state?: 'running' | 'completed' | 'error' | 'cancelled';
+  result?: string;
+  terminateReason?: AgentTerminateMode;
 }
 
 export function isSubagentProgress(obj: unknown): obj is SubagentProgress {

packages/core/src/index.ts

@@ -118,6 +118,7 @@ export * from './utils/channel.js';
 export * from './utils/constants.js';
 export * from './utils/sessionUtils.js';
 export * from './utils/cache.js';
+export * from './utils/markdownUtils.js';
 
 // Export services
 export * from './services/fileDiscoveryService.js';