Cleanup post delegate_to_agent removal (#17875)

packages/cli/src/ui/hooks/atCommandProcessor.test.ts

@@ -45,6 +45,7 @@ describe('handleAtCommand', () => {
   }
 
   beforeEach(async () => {
+    vi.restoreAllMocks();
     vi.resetAllMocks();
 
     testRootDir = await fsPromises.mkdtemp(
@@ -1403,4 +1404,32 @@ describe('handleAtCommand', () => {
       134,
     );
   });
+
+  it('should include agent nudge when agents are found', async () => {
+    const agentName = 'my-agent';
+    const otherAgent = 'other-agent';
+
+    // Mock getAgentRegistry on the config
+    mockConfig.getAgentRegistry = vi.fn().mockReturnValue({
+      getDefinition: (name: string) =>
+        name === agentName || name === otherAgent ? { name } : undefined,
+    });
+
+    const query = `@${agentName} @${otherAgent}`;
+
+    const result = await handleAtCommand({
+      query,
+      config: mockConfig,
+      addItem: mockAddItem,
+      onDebugMessage: mockOnDebugMessage,
+      messageId: 600,
+      signal: abortController.signal,
+    });
+
+    const expectedNudge = `\n<system_note>\nThe user has explicitly selected the following agent(s): ${agentName}, ${otherAgent}. Please use the following tool(s) to delegate the task: '${agentName}', '${otherAgent}'.\n</system_note>\n`;
+
+    expect(result.processedQuery).toContainEqual(
+      expect.objectContaining({ text: expectedNudge }),
+    );
+  });
 });