fix: ACP: separate conversational text from execute tool command title (#23179)

packages/cli/src/acp/acpClient.test.ts

@@ -1080,6 +1080,70 @@ describe('Session', () => {
     );
   });
 
+  it('should split getDisplayTitle and getExplanation for title and content in permission request', async () => {
+    const confirmationDetails = {
+      type: 'info',
+      onConfirm: vi.fn(),
+    };
+    mockTool.build.mockReturnValue({
+      getDescription: () => 'Original Description',
+      getDisplayTitle: () => 'Display Title Only',
+      getExplanation: () => 'A detailed explanation text',
+      toolLocations: () => [],
+      shouldConfirmExecute: vi.fn().mockResolvedValue(confirmationDetails),
+      execute: vi.fn().mockResolvedValue({ llmContent: 'Tool Result' }),
+    });
+
+    mockConnection.requestPermission.mockResolvedValue({
+      outcome: {
+        outcome: 'selected',
+        optionId: ToolConfirmationOutcome.ProceedOnce,
+      },
+    });
+
+    const stream1 = createMockStream([
+      {
+        type: StreamEventType.CHUNK,
+        value: {
+          functionCalls: [{ name: 'test_tool', args: {} }],
+        },
+      },
+    ]);
+    const stream2 = createMockStream([
+      {
+        type: StreamEventType.CHUNK,
+        value: { candidates: [] },
+      },
+    ]);
+
+    mockChat.sendMessageStream
+      .mockResolvedValueOnce(stream1)
+      .mockResolvedValueOnce(stream2);
+
+    await session.prompt({
+      sessionId: 'session-1',
+      prompt: [{ type: 'text', text: 'Call tool' }],
+    });
+
+    expect(mockConnection.requestPermission).toHaveBeenCalledWith(
+      expect.objectContaining({
+        toolCall: expect.objectContaining({
+          title: 'Display Title Only',
+          content: [],
+        }),
+      }),
+    );
+
+    expect(mockConnection.sessionUpdate).toHaveBeenCalledWith(
+      expect.objectContaining({
+        update: expect.objectContaining({
+          sessionUpdate: 'agent_thought_chunk',
+          content: { type: 'text', text: 'A detailed explanation text' },
+        }),
+      }),
+    );
+  });
+
   it('should use filePath for ACP diff content in tool result', async () => {
     mockTool.build.mockReturnValue({
       getDescription: () => 'Test Tool',

packages/cli/src/acp/acpClient.ts

@@ -947,6 +947,23 @@ export class Session {
     try {
       const invocation = tool.build(args);
 
+      const displayTitle =
+        typeof invocation.getDisplayTitle === 'function'
+          ? invocation.getDisplayTitle()
+          : invocation.getDescription();
+
+      const explanation =
+        typeof invocation.getExplanation === 'function'
+          ? invocation.getExplanation()
+          : '';
+
+      if (explanation) {
+        await this.sendUpdate({
+          sessionUpdate: 'agent_thought_chunk',
+          content: { type: 'text', text: explanation },
+        });
+      }
+
       const confirmationDetails =
         await invocation.shouldConfirmExecute(abortSignal);
 
@@ -978,7 +995,7 @@ export class Session {
           toolCall: {
             toolCallId: callId,
             status: 'pending',
-            title: invocation.getDescription(),
+            title: displayTitle,
             content,
             locations: invocation.toolLocations(),
             kind: toAcpToolKind(tool.kind),
@@ -1014,12 +1031,14 @@ export class Session {
           }
         }
       } else {
+        const content: acp.ToolCallContent[] = [];
+
         await this.sendUpdate({
           sessionUpdate: 'tool_call',
           toolCallId: callId,
           status: 'in_progress',
-          title: invocation.getDescription(),
-          content: [],
+          title: displayTitle,
+          content,
           locations: invocation.toolLocations(),
           kind: toAcpToolKind(tool.kind),
         });
@@ -1028,12 +1047,14 @@ export class Session {
       const toolResult: ToolResult = await invocation.execute(abortSignal);
       const content = toToolCallContent(toolResult);
 
+      const updateContent: acp.ToolCallContent[] = content ? [content] : [];
+
       await this.sendUpdate({
         sessionUpdate: 'tool_call_update',
         toolCallId: callId,
         status: 'completed',
-        title: invocation.getDescription(),
-        content: content ? [content] : [],
+        title: displayTitle,
+        content: updateContent,
         locations: invocation.toolLocations(),
         kind: toAcpToolKind(tool.kind),
       });