fix(core): stop spinners for running activities on remote session error/abort

packages/core/src/agents/remote-session-invocation.test.ts

@@ -1,6 +1,6 @@
 /**
  * @license
- * Copyright 2025 Google LLC
+ * Copyright 2026 Google LLC
  * SPDX-License-Identifier: Apache-2.0
  */
 
@@ -354,7 +354,22 @@ describe('RemoteSessionInvocation', () => {
     it('should handle abort gracefully', async () => {
       const controller = new AbortController();
 
-      const { mockSession } = setupMockSession();
+      const partialProgress: SubagentProgress = {
+        isSubagentProgress: true,
+        agentName: 'Test Agent',
+        state: SubagentState.RUNNING,
+        result: '',
+        recentActivity: [
+          {
+            id: 'a1',
+            type: 'thought',
+            content: 'Thinking...',
+            status: SubagentState.RUNNING,
+          },
+        ],
+      };
+
+      const { mockSession } = setupMockSession({ progress: partialProgress });
 
       // When getResult resolves, the signal will already be aborted
       mockSession.getResult.mockImplementation(async () => {
@@ -378,7 +393,10 @@ describe('RemoteSessionInvocation', () => {
         updateOutput,
       });
 
-      expect(result.returnDisplay).toMatchObject({ state: 'error' });
+      expect(result.returnDisplay).toMatchObject({ state: 'cancelled' });
+      expect(
+        (result.returnDisplay as SubagentProgress).recentActivity[0].status,
+      ).toBe(SubagentState.CANCELLED);
       expect(result.llmContent).toEqual([
         { text: 'Operation cancelled by user' },
       ]);
@@ -452,9 +470,10 @@ describe('RemoteSessionInvocation', () => {
       // Should contain both the partial output and the error
       expect(display.result).toContain('Partial work so far');
       expect(display.result).toContain('mid-stream error');
-      // Should preserve partial activity
+      // Should preserve and update partial activity status to ERROR
       expect(display.recentActivity).toHaveLength(1);
       expect(display.recentActivity[0].content).toBe('Thinking...');
+      expect(display.recentActivity[0].status).toBe(SubagentState.ERROR);
     });
 
     it('should clean up listeners in finally', async () => {

packages/core/src/agents/remote-session-invocation.ts

@@ -1,6 +1,6 @@
 /**
  * @license
- * Copyright 2025 Google LLC
+ * Copyright 2026 Google LLC
  * SPDX-License-Identifier: Apache-2.0
  */
 
@@ -17,6 +17,7 @@ import {
   type RemoteAgentDefinition,
   type AgentInputs,
   type SubagentProgress,
+  type SubagentActivityItem,
   SubagentState,
   getRemoteAgentTargetUrl,
 } from './types.js';
@@ -116,6 +117,7 @@ export class RemoteSessionInvocation extends BaseToolInvocation<
   async execute(options: ExecuteOptions): Promise<ToolResult> {
     const { abortSignal: _signal, updateOutput } = options;
     const agentName = this.definition.displayName ?? this.definition.name;
+    const emptyActivity: SubagentActivityItem[] = [];
 
     // Seed session with prior A2A conversation state
     const stateKey = RemoteSessionInvocation.sessionKey(this.definition);
@@ -172,15 +174,19 @@ export class RemoteSessionInvocation extends BaseToolInvocation<
       // rejecting. Detect this and surface proper error state.
       if (_signal?.aborted) {
         const partialProgress = session.getLatestProgress();
+        const recentActivity = this.stopRunningActivities(
+          partialProgress?.recentActivity ?? emptyActivity,
+          SubagentState.CANCELLED,
+        );
         const errorProgress: SubagentProgress = {
           isSubagentProgress: true,
           agentName,
-          state: SubagentState.ERROR,
+          state: SubagentState.CANCELLED,
           result:
             typeof partialProgress?.result === 'string'
               ? partialProgress.result
               : '',
-          recentActivity: partialProgress?.recentActivity ?? [],
+          recentActivity,
         };
         if (updateOutput) updateOutput(errorProgress);
         return {
@@ -207,12 +213,22 @@ export class RemoteSessionInvocation extends BaseToolInvocation<
         ? `${partialOutput}\n\n${errorMessage}`
         : errorMessage;
 
+      const isAbort =
+        (error instanceof Error && error.name === 'AbortError') ||
+        errorMessage.includes('Aborted');
+
+      const status = isAbort ? SubagentState.CANCELLED : SubagentState.ERROR;
+      const recentActivity = this.stopRunningActivities(
+        partialProgress?.recentActivity ?? emptyActivity,
+        status,
+      );
+
       const errorProgress: SubagentProgress = {
         isSubagentProgress: true,
         agentName,
-        state: SubagentState.ERROR,
+        state: status,
         result: fullDisplay,
-        recentActivity: partialProgress?.recentActivity ?? [],
+        recentActivity,
       };
 
       if (updateOutput) {
@@ -235,6 +251,19 @@ export class RemoteSessionInvocation extends BaseToolInvocation<
     }
   }
 
+  private stopRunningActivities(
+    activity: SubagentActivityItem[],
+    status: SubagentState,
+  ): SubagentActivityItem[] {
+    const result: SubagentActivityItem[] = [];
+    for (const item of activity) {
+      result.push(
+        item.status === SubagentState.RUNNING ? { ...item, status } : item,
+      );
+    }
+    return result;
+  }
+
   /**
    * Formats an execution error into a user-friendly message.
    * Recognizes typed A2AAgentError subclasses and falls back to