feat(core): subagent local execution and tool isolation (#22718)

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

@@ -13,10 +13,43 @@ import {
   afterEach,
   type Mock,
 } from 'vitest';
+
+const {
+  mockSendMessageStream,
+  mockScheduleAgentTools,
+  mockSetSystemInstruction,
+  mockCompress,
+  mockMaybeDiscoverMcpServer,
+  mockStopMcp,
+} = vi.hoisted(() => ({
+  mockSendMessageStream: vi.fn().mockResolvedValue({
+    async *[Symbol.asyncIterator]() {
+      yield {
+        type: 'chunk',
+        value: { candidates: [] },
+      };
+    },
+  }),
+  mockScheduleAgentTools: vi.fn(),
+  mockSetSystemInstruction: vi.fn(),
+  mockCompress: vi.fn(),
+  mockMaybeDiscoverMcpServer: vi.fn().mockResolvedValue(undefined),
+  mockStopMcp: vi.fn().mockResolvedValue(undefined),
+}));
+
+vi.mock('../tools/mcp-client-manager.js', () => ({
+  McpClientManager: class {
+    maybeDiscoverMcpServer = mockMaybeDiscoverMcpServer;
+    stop = mockStopMcp;
+  },
+}));
+
 import { debugLogger } from '../utils/debugLogger.js';
 import { LocalAgentExecutor, type ActivityCallback } from './local-executor.js';
 import { makeFakeConfig } from '../test-utils/config.js';
 import { ToolRegistry } from '../tools/tool-registry.js';
+import { PromptRegistry } from '../prompts/prompt-registry.js';
+import { ResourceRegistry } from '../resources/resource-registry.js';
 import { DiscoveredMCPTool } from '../tools/mcp-tool.js';
 import { LSTool } from '../tools/ls.js';
 import { LS_TOOL_NAME, READ_FILE_TOOL_NAME } from '../tools/tool-names.js';
@@ -70,18 +103,6 @@ import type {
 import { getModelConfigAlias, type AgentRegistry } from './registry.js';
 import type { ModelRouterService } from '../routing/modelRouterService.js';
 
-const {
-  mockSendMessageStream,
-  mockScheduleAgentTools,
-  mockSetSystemInstruction,
-  mockCompress,
-} = vi.hoisted(() => ({
-  mockSendMessageStream: vi.fn(),
-  mockScheduleAgentTools: vi.fn(),
-  mockSetSystemInstruction: vi.fn(),
-  mockCompress: vi.fn(),
-}));
-
 let mockChatHistory: Content[] = [];
 const mockSetHistory = vi.fn((newHistory: Content[]) => {
   mockChatHistory = newHistory;
@@ -2722,6 +2743,67 @@ describe('LocalAgentExecutor', () => {
     });
   });
 
+  describe('MCP Isolation', () => {
+    it('should initialize McpClientManager when mcpServers are defined', async () => {
+      const { MCPServerConfig } = await import('../config/config.js');
+      const mcpServers = {
+        'test-server': new MCPServerConfig('node', ['server.js']),
+      };
+
+      const definition = {
+        ...createTestDefinition(),
+        mcpServers,
+      };
+
+      vi.spyOn(mockConfig, 'getMcpClientManager').mockReturnValue({
+        maybeDiscoverMcpServer: mockMaybeDiscoverMcpServer,
+      } as unknown as ReturnType<typeof mockConfig.getMcpClientManager>);
+
+      await LocalAgentExecutor.create(definition, mockConfig);
+
+      const mcpManager = mockConfig.getMcpClientManager();
+      expect(mcpManager?.maybeDiscoverMcpServer).toHaveBeenCalledWith(
+        'test-server',
+        mcpServers['test-server'],
+        expect.objectContaining({
+          toolRegistry: expect.any(ToolRegistry),
+          promptRegistry: expect.any(PromptRegistry),
+          resourceRegistry: expect.any(ResourceRegistry),
+        }),
+      );
+    });
+
+    it('should inherit main registry tools', async () => {
+      const parentMcpTool = new DiscoveredMCPTool(
+        {} as unknown as CallableTool,
+        'main-server',
+        'tool1',
+        'desc1',
+        {},
+        mockConfig.getMessageBus(),
+      );
+
+      parentToolRegistry.registerTool(parentMcpTool);
+
+      const definition = createTestDefinition();
+      definition.toolConfig = undefined; // trigger inheritance
+
+      vi.spyOn(mockConfig, 'getMcpClientManager').mockReturnValue({
+        maybeDiscoverMcpServer: vi.fn(),
+      } as unknown as ReturnType<typeof mockConfig.getMcpClientManager>);
+      const executor = await LocalAgentExecutor.create(
+        definition,
+        mockConfig,
+        onActivity,
+      );
+      const agentTools = (
+        executor as unknown as { toolRegistry: ToolRegistry }
+      ).toolRegistry.getAllToolNames();
+
+      expect(agentTools).toContain(parentMcpTool.name);
+    });
+  });
+
   describe('DeclarativeTool instance tools (browser agent pattern)', () => {
     /**
      * The browser agent passes DeclarativeTool instances (not string names) in
@@ -2827,13 +2909,11 @@ describe('LocalAgentExecutor', () => {
       const navTool = new MockTool({ name: 'navigate_page' });
 
       const definition = createInstanceToolDefinition([clickTool, navTool]);
-
       const executor = await LocalAgentExecutor.create(
         definition,
         mockConfig,
         onActivity,
       );
-
       const registry = executor['toolRegistry'];
       expect(registry.getTool('click')).toBeDefined();
       expect(registry.getTool('navigate_page')).toBeDefined();