Cleanup post delegate_to_agent removal (#17875)

docs/core/policy-engine.md

@@ -295,9 +295,9 @@ The Gemini CLI ships with a set of default policies to provide a safe
 out-of-the-box experience.
 
 - **Read-only tools** (like `read_file`, `glob`) are generally **allowed**.
-- **Agent delegation** (like `delegate_to_agent`) defaults to **`ask_user`** to
-  ensure remote agents can prompt for confirmation, but local sub-agent actions
-  are executed silently and checked individually.
+- **Agent delegation** defaults to **`ask_user`** to ensure remote agents can
+  prompt for confirmation, but local sub-agent actions are executed silently and
+  checked individually.
 - **Write tools** (like `write_file`, `run_shell_command`) default to
   **`ask_user`**.
 - In **`yolo`** mode, a high-priority rule allows all tools.

evals/generalist_agent.eval.ts

@@ -24,11 +24,11 @@ describe('generalist_agent', () => {
     prompt:
       'Please use the generalist agent to create a file called "generalist_test_file.txt" containing exactly the following text: success',
     assert: async (rig) => {
-      // 1) Verify the generalist agent was invoked via delegate_to_agent
+      // 1) Verify the generalist agent was invoked
       const foundToolCall = await rig.waitForToolCall('generalist');
       expect(
         foundToolCall,
-        'Expected to find a delegate_to_agent tool call for generalist agent',
+        'Expected to find a tool call for generalist agent',
       ).toBeTruthy();
 
       // 2) Verify the file was created as expected

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 }),
+    );
+  });
 });

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

@@ -457,9 +457,10 @@ export async function handleAtCommand({
   const processedQueryParts: PartListUnion = [{ text: initialQueryText }];
 
   if (agentsFound.length > 0) {
+    const toolsList = agentsFound.map((agent) => `'${agent}'`).join(', ');
     const agentNudge = `\n<system_note>\nThe user has explicitly selected the following agent(s): ${agentsFound.join(
       ', ',
-    )}. Please use the 'delegate_to_agent' tool to delegate the task to the selected agent(s).\n</system_note>\n`;
+    )}. Please use the following tool(s) to delegate the task: ${toolsList}.\n</system_note>\n`;
     processedQueryParts.push({ text: agentNudge });
   }
 

packages/core/src/policy/policies/agent.toml

@@ -25,7 +25,3 @@
 #   50: Read-only tools (becomes 1.050 in default tier)
 #   999: YOLO mode allow-all (becomes 1.999 in default tier)
 
-[[rule]]
-toolName = "delegate_to_agent"
-decision = "ask_user"
-priority = 50