refactor: Extract MCP discovery from ToolRegistry
- Moves MCP tool discovery logic from ToolRegistry into a new, dedicated MCP client (mcp-client.ts and mcp-tool.ts). - Updates ToolRegistry to utilize the new MCP client. - Adds comprehensive tests for the new MCP client and its integration with ToolRegistry. Part of https://github.com/google-gemini/gemini-cli/issues/577
This commit is contained in:
Taylor Mullen
N. Taylor Mullen
parent
c413988ae0
commit
d74c0f581b
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@ -0,0 +1,371 @@
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/**
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* @license
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* Copyright 2025 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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/* eslint-disable @typescript-eslint/no-explicit-any */
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import {
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describe,
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it,
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expect,
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vi,
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beforeEach,
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afterEach,
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Mocked,
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} from 'vitest';
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import { discoverMcpTools } from './mcp-client.js';
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import { Config, MCPServerConfig } from '../config/config.js';
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import { ToolRegistry } from './tool-registry.js';
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import { DiscoveredMCPTool } from './mcp-tool.js';
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import { Client } from '@modelcontextprotocol/sdk/client/index.js';
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import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
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import { SSEClientTransport } from '@modelcontextprotocol/sdk/client/sse.js';
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import { parse, ParseEntry } from 'shell-quote';
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// Mock dependencies
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vi.mock('shell-quote');
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vi.mock('@modelcontextprotocol/sdk/client/index.js', () => {
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const MockedClient = vi.fn();
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MockedClient.prototype.connect = vi.fn();
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MockedClient.prototype.listTools = vi.fn();
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// Ensure instances have an onerror property that can be spied on or assigned to
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MockedClient.mockImplementation(() => ({
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connect: MockedClient.prototype.connect,
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listTools: MockedClient.prototype.listTools,
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onerror: vi.fn(), // Each instance gets its own onerror mock
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}));
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return { Client: MockedClient };
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});
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// Define a global mock for stderr.on that can be cleared and checked
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const mockGlobalStdioStderrOn = vi.fn();
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vi.mock('@modelcontextprotocol/sdk/client/stdio.js', () => {
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// This is the constructor for StdioClientTransport
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const MockedStdioTransport = vi.fn().mockImplementation(function (
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this: any,
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options: any,
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) {
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// Always return a new object with a fresh reference to the global mock for .on
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this.options = options;
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this.stderr = { on: mockGlobalStdioStderrOn };
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return this;
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});
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return { StdioClientTransport: MockedStdioTransport };
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});
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vi.mock('@modelcontextprotocol/sdk/client/sse.js', () => {
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const MockedSSETransport = vi.fn();
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return { SSEClientTransport: MockedSSETransport };
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});
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vi.mock('./tool-registry.js');
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describe('discoverMcpTools', () => {
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let mockConfig: Mocked<Config>;
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let mockToolRegistry: Mocked<ToolRegistry>;
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beforeEach(() => {
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mockConfig = {
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getMcpServers: vi.fn().mockReturnValue({}),
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getMcpServerCommand: vi.fn().mockReturnValue(undefined),
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} as any;
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mockToolRegistry = new (ToolRegistry as any)(
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mockConfig,
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) as Mocked<ToolRegistry>;
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mockToolRegistry.registerTool = vi.fn();
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vi.mocked(parse).mockClear();
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vi.mocked(Client).mockClear();
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vi.mocked(Client.prototype.connect)
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.mockClear()
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.mockResolvedValue(undefined);
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vi.mocked(Client.prototype.listTools)
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.mockClear()
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.mockResolvedValue({ tools: [] });
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vi.mocked(StdioClientTransport).mockClear();
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mockGlobalStdioStderrOn.mockClear(); // Clear the global mock in beforeEach
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vi.mocked(SSEClientTransport).mockClear();
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});
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afterEach(() => {
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vi.restoreAllMocks();
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});
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it('should do nothing if no MCP servers or command are configured', async () => {
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await discoverMcpTools(mockConfig, mockToolRegistry);
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expect(mockConfig.getMcpServers).toHaveBeenCalledTimes(1);
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expect(mockConfig.getMcpServerCommand).toHaveBeenCalledTimes(1);
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expect(Client).not.toHaveBeenCalled();
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expect(mockToolRegistry.registerTool).not.toHaveBeenCalled();
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});
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it('should discover tools via mcpServerCommand', async () => {
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const commandString = 'my-mcp-server --start';
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const parsedCommand = ['my-mcp-server', '--start'] as ParseEntry[];
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mockConfig.getMcpServerCommand.mockReturnValue(commandString);
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vi.mocked(parse).mockReturnValue(parsedCommand);
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const mockTool = {
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name: 'tool1',
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description: 'desc1',
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inputSchema: { type: 'object' as const, properties: {} },
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};
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vi.mocked(Client.prototype.listTools).mockResolvedValue({
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tools: [mockTool],
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});
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await discoverMcpTools(mockConfig, mockToolRegistry);
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expect(parse).toHaveBeenCalledWith(commandString, process.env);
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expect(StdioClientTransport).toHaveBeenCalledWith({
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command: parsedCommand[0],
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args: parsedCommand.slice(1),
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env: expect.any(Object),
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cwd: undefined,
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stderr: 'pipe',
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});
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expect(Client.prototype.connect).toHaveBeenCalledTimes(1);
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expect(Client.prototype.listTools).toHaveBeenCalledTimes(1);
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expect(mockToolRegistry.registerTool).toHaveBeenCalledTimes(1);
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expect(mockToolRegistry.registerTool).toHaveBeenCalledWith(
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expect.any(DiscoveredMCPTool),
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);
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const registeredTool = mockToolRegistry.registerTool.mock
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.calls[0][0] as DiscoveredMCPTool;
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expect(registeredTool.name).toBe('tool1');
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expect(registeredTool.serverToolName).toBe('tool1');
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});
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it('should discover tools via mcpServers config (stdio)', async () => {
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const serverConfig: MCPServerConfig = {
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command: './mcp-stdio',
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args: ['arg1'],
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};
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mockConfig.getMcpServers.mockReturnValue({ 'stdio-server': serverConfig });
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const mockTool = {
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name: 'tool-stdio',
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description: 'desc-stdio',
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inputSchema: { type: 'object' as const, properties: {} },
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};
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vi.mocked(Client.prototype.listTools).mockResolvedValue({
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tools: [mockTool],
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});
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await discoverMcpTools(mockConfig, mockToolRegistry);
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expect(StdioClientTransport).toHaveBeenCalledWith({
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command: serverConfig.command,
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args: serverConfig.args,
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env: expect.any(Object),
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cwd: undefined,
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stderr: 'pipe',
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});
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expect(mockToolRegistry.registerTool).toHaveBeenCalledWith(
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expect.any(DiscoveredMCPTool),
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);
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const registeredTool = mockToolRegistry.registerTool.mock
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.calls[0][0] as DiscoveredMCPTool;
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expect(registeredTool.name).toBe('tool-stdio');
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});
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it('should discover tools via mcpServers config (sse)', async () => {
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const serverConfig: MCPServerConfig = { url: 'http://localhost:1234/sse' };
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mockConfig.getMcpServers.mockReturnValue({ 'sse-server': serverConfig });
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const mockTool = {
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name: 'tool-sse',
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description: 'desc-sse',
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inputSchema: { type: 'object' as const, properties: {} },
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};
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vi.mocked(Client.prototype.listTools).mockResolvedValue({
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tools: [mockTool],
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});
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await discoverMcpTools(mockConfig, mockToolRegistry);
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expect(SSEClientTransport).toHaveBeenCalledWith(new URL(serverConfig.url!));
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expect(mockToolRegistry.registerTool).toHaveBeenCalledWith(
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expect.any(DiscoveredMCPTool),
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);
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const registeredTool = mockToolRegistry.registerTool.mock
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.calls[0][0] as DiscoveredMCPTool;
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expect(registeredTool.name).toBe('tool-sse');
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});
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it('should prefix tool names if multiple MCP servers are configured', async () => {
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const serverConfig1: MCPServerConfig = { command: './mcp1' };
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const serverConfig2: MCPServerConfig = { url: 'http://mcp2/sse' };
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mockConfig.getMcpServers.mockReturnValue({
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server1: serverConfig1,
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server2: serverConfig2,
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});
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const mockTool1 = {
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name: 'toolA',
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description: 'd1',
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inputSchema: { type: 'object' as const, properties: {} },
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};
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const mockTool2 = {
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name: 'toolB',
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description: 'd2',
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inputSchema: { type: 'object' as const, properties: {} },
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};
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vi.mocked(Client.prototype.listTools)
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.mockResolvedValueOnce({ tools: [mockTool1] })
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.mockResolvedValueOnce({ tools: [mockTool2] });
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await discoverMcpTools(mockConfig, mockToolRegistry);
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expect(mockToolRegistry.registerTool).toHaveBeenCalledTimes(2);
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const registeredTool1 = mockToolRegistry.registerTool.mock
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.calls[0][0] as DiscoveredMCPTool;
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const registeredTool2 = mockToolRegistry.registerTool.mock
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.calls[1][0] as DiscoveredMCPTool;
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expect(registeredTool1.name).toBe('server1__toolA');
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expect(registeredTool1.serverToolName).toBe('toolA');
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expect(registeredTool2.name).toBe('server2__toolB');
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expect(registeredTool2.serverToolName).toBe('toolB');
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});
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it('should clean schema properties ($schema, additionalProperties)', async () => {
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const serverConfig: MCPServerConfig = { command: './mcp-clean' };
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mockConfig.getMcpServers.mockReturnValue({ 'clean-server': serverConfig });
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const rawSchema = {
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type: 'object' as const,
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$schema: 'http://json-schema.org/draft-07/schema#',
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additionalProperties: true,
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properties: {
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prop1: { type: 'string', $schema: 'remove-this' },
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prop2: {
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type: 'object' as const,
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additionalProperties: false,
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properties: { nested: { type: 'number' } },
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},
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},
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};
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const mockTool = {
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name: 'cleanTool',
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description: 'd',
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inputSchema: JSON.parse(JSON.stringify(rawSchema)),
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};
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vi.mocked(Client.prototype.listTools).mockResolvedValue({
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tools: [mockTool],
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});
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await discoverMcpTools(mockConfig, mockToolRegistry);
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expect(mockToolRegistry.registerTool).toHaveBeenCalledTimes(1);
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const registeredTool = mockToolRegistry.registerTool.mock
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.calls[0][0] as DiscoveredMCPTool;
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const cleanedParams = registeredTool.schema.parameters as any;
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expect(cleanedParams).not.toHaveProperty('$schema');
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expect(cleanedParams).not.toHaveProperty('additionalProperties');
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expect(cleanedParams.properties.prop1).not.toHaveProperty('$schema');
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expect(cleanedParams.properties.prop2).not.toHaveProperty(
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'additionalProperties',
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);
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expect(cleanedParams.properties.prop2.properties.nested).not.toHaveProperty(
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'$schema',
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);
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expect(cleanedParams.properties.prop2.properties.nested).not.toHaveProperty(
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'additionalProperties',
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);
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});
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it('should handle error if mcpServerCommand parsing fails', async () => {
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const commandString = 'my-mcp-server "unterminated quote';
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mockConfig.getMcpServerCommand.mockReturnValue(commandString);
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vi.mocked(parse).mockImplementation(() => {
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throw new Error('Parsing failed');
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});
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vi.spyOn(console, 'error').mockImplementation(() => {});
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await expect(
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discoverMcpTools(mockConfig, mockToolRegistry),
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).rejects.toThrow('Parsing failed');
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expect(mockToolRegistry.registerTool).not.toHaveBeenCalled();
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expect(console.error).not.toHaveBeenCalled();
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});
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it('should log error and skip server if config is invalid (missing url and command)', async () => {
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mockConfig.getMcpServers.mockReturnValue({ 'bad-server': {} as any });
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vi.spyOn(console, 'error').mockImplementation(() => {});
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await discoverMcpTools(mockConfig, mockToolRegistry);
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expect(console.error).toHaveBeenCalledWith(
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expect.stringContaining(
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"MCP server 'bad-server' has invalid configuration",
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),
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);
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// Client constructor should not be called if config is invalid before instantiation
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expect(Client).not.toHaveBeenCalled();
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});
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it('should log error and skip server if mcpClient.connect fails', async () => {
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const serverConfig: MCPServerConfig = { command: './mcp-fail-connect' };
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mockConfig.getMcpServers.mockReturnValue({
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'fail-connect-server': serverConfig,
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});
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vi.mocked(Client.prototype.connect).mockRejectedValue(
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new Error('Connection refused'),
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);
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vi.spyOn(console, 'error').mockImplementation(() => {});
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await discoverMcpTools(mockConfig, mockToolRegistry);
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expect(console.error).toHaveBeenCalledWith(
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expect.stringContaining(
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"failed to start or connect to MCP server 'fail-connect-server'",
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),
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);
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expect(Client.prototype.listTools).not.toHaveBeenCalled();
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expect(mockToolRegistry.registerTool).not.toHaveBeenCalled();
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});
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it('should log error and skip server if mcpClient.listTools fails', async () => {
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const serverConfig: MCPServerConfig = { command: './mcp-fail-list' };
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mockConfig.getMcpServers.mockReturnValue({
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'fail-list-server': serverConfig,
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});
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vi.mocked(Client.prototype.listTools).mockRejectedValue(
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new Error('ListTools error'),
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);
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vi.spyOn(console, 'error').mockImplementation(() => {});
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await discoverMcpTools(mockConfig, mockToolRegistry);
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expect(console.error).toHaveBeenCalledWith(
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expect.stringContaining(
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"Failed to list or register tools for MCP server 'fail-list-server'",
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),
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);
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expect(mockToolRegistry.registerTool).not.toHaveBeenCalled();
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});
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it('should assign mcpClient.onerror handler', async () => {
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const serverConfig: MCPServerConfig = { command: './mcp-onerror' };
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mockConfig.getMcpServers.mockReturnValue({
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'onerror-server': serverConfig,
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});
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await discoverMcpTools(mockConfig, mockToolRegistry);
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const clientInstances = vi.mocked(Client).mock.results;
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expect(clientInstances.length).toBeGreaterThan(0);
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const lastClientInstance =
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clientInstances[clientInstances.length - 1]?.value;
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expect(lastClientInstance?.onerror).toEqual(expect.any(Function));
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});
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});
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@ -0,0 +1,138 @@
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/**
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* @license
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* Copyright 2025 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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import { Client } from '@modelcontextprotocol/sdk/client/index.js';
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import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
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import { SSEClientTransport } from '@modelcontextprotocol/sdk/client/sse.js';
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import { parse } from 'shell-quote';
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import { Config, MCPServerConfig } from '../config/config.js';
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import { DiscoveredMCPTool } from './mcp-tool.js';
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import { ToolRegistry } from './tool-registry.js';
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export async function discoverMcpTools(
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config: Config,
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toolRegistry: ToolRegistry,
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): Promise<void> {
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const mcpServers = config.getMcpServers() || {};
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if (config.getMcpServerCommand()) {
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const cmd = config.getMcpServerCommand()!;
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const args = parse(cmd, process.env) as string[];
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if (args.some((arg) => typeof arg !== 'string')) {
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throw new Error('failed to parse mcpServerCommand: ' + cmd);
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}
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// use generic server name 'mcp'
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mcpServers['mcp'] = {
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command: args[0],
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args: args.slice(1),
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};
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}
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const discoveryPromises = Object.entries(mcpServers).map(
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([mcpServerName, mcpServerConfig]) =>
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connectAndDiscover(
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mcpServerName,
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mcpServerConfig,
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toolRegistry,
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mcpServers,
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),
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);
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await Promise.all(discoveryPromises);
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}
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async function connectAndDiscover(
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mcpServerName: string,
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mcpServerConfig: MCPServerConfig,
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toolRegistry: ToolRegistry,
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mcpServers: Record<string, MCPServerConfig>,
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): Promise<void> {
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let transport;
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if (mcpServerConfig.url) {
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transport = new SSEClientTransport(new URL(mcpServerConfig.url));
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} else if (mcpServerConfig.command) {
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transport = new StdioClientTransport({
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command: mcpServerConfig.command,
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args: mcpServerConfig.args || [],
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env: {
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...process.env,
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...(mcpServerConfig.env || {}),
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} as Record<string, string>,
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cwd: mcpServerConfig.cwd,
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stderr: 'pipe',
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});
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} else {
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console.error(
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`MCP server '${mcpServerName}' has invalid configuration: missing both url (for SSE) and command (for stdio). Skipping.`,
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);
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return; // Return a resolved promise as this path doesn't throw.
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}
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const mcpClient = new Client({
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name: 'gemini-cli-mcp-client',
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version: '0.0.1',
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});
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try {
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await mcpClient.connect(transport);
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} catch (error) {
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console.error(
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`failed to start or connect to MCP server '${mcpServerName}' ` +
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`${JSON.stringify(mcpServerConfig)}; \n${error}`,
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);
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return; // Return a resolved promise, let other MCP servers be discovered.
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}
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mcpClient.onerror = (error) => {
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||||
console.error('MCP ERROR', error.toString());
|
||||
};
|
||||
|
||||
if (transport instanceof StdioClientTransport && transport.stderr) {
|
||||
transport.stderr.on('data', (data) => {
|
||||
if (!data.toString().includes('] INFO')) {
|
||||
console.debug('MCP STDERR', data.toString());
|
||||
}
|
||||
});
|
||||
}
|
||||
|
||||
try {
|
||||
const result = await mcpClient.listTools();
|
||||
for (const tool of result.tools) {
|
||||
// Recursively remove additionalProperties and $schema from the inputSchema
|
||||
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- This function recursively navigates a deeply nested and potentially heterogeneous JSON schema object. Using 'any' is a pragmatic choice here to avoid overly complex type definitions for all possible schema variations.
|
||||
const removeSchemaProps = (obj: any) => {
|
||||
if (typeof obj !== 'object' || obj === null) {
|
||||
return;
|
||||
}
|
||||
if (Array.isArray(obj)) {
|
||||
obj.forEach(removeSchemaProps);
|
||||
} else {
|
||||
delete obj.additionalProperties;
|
||||
delete obj.$schema;
|
||||
Object.values(obj).forEach(removeSchemaProps);
|
||||
}
|
||||
};
|
||||
removeSchemaProps(tool.inputSchema);
|
||||
|
||||
toolRegistry.registerTool(
|
||||
new DiscoveredMCPTool(
|
||||
mcpClient,
|
||||
Object.keys(mcpServers).length > 1
|
||||
? mcpServerName + '__' + tool.name
|
||||
: tool.name,
|
||||
tool.description ?? '',
|
||||
tool.inputSchema,
|
||||
tool.name,
|
||||
mcpServerConfig.timeout,
|
||||
),
|
||||
);
|
||||
}
|
||||
} catch (error) {
|
||||
console.error(
|
||||
`Failed to list or register tools for MCP server '${mcpServerName}': ${error}`,
|
||||
);
|
||||
// Do not re-throw, allow other servers to proceed.
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,161 @@
|
|||
/**
|
||||
* @license
|
||||
* Copyright 2025 Google LLC
|
||||
* SPDX-License-Identifier: Apache-2.0
|
||||
*/
|
||||
|
||||
/* eslint-disable @typescript-eslint/no-explicit-any */
|
||||
import {
|
||||
describe,
|
||||
it,
|
||||
expect,
|
||||
vi,
|
||||
beforeEach,
|
||||
afterEach,
|
||||
Mocked,
|
||||
} from 'vitest';
|
||||
import {
|
||||
DiscoveredMCPTool,
|
||||
MCP_TOOL_DEFAULT_TIMEOUT_MSEC,
|
||||
} from './mcp-tool.js';
|
||||
import { Client } from '@modelcontextprotocol/sdk/client/index.js';
|
||||
import { ToolResult } from './tools.js';
|
||||
|
||||
// Mock MCP SDK Client
|
||||
vi.mock('@modelcontextprotocol/sdk/client/index.js', () => {
|
||||
const MockClient = vi.fn();
|
||||
MockClient.prototype.callTool = vi.fn();
|
||||
return { Client: MockClient };
|
||||
});
|
||||
|
||||
describe('DiscoveredMCPTool', () => {
|
||||
let mockMcpClient: Mocked<Client>;
|
||||
const toolName = 'test-mcp-tool';
|
||||
const serverToolName = 'actual-server-tool-name';
|
||||
const baseDescription = 'A test MCP tool.';
|
||||
const inputSchema = {
|
||||
type: 'object' as const,
|
||||
properties: { param: { type: 'string' } },
|
||||
};
|
||||
|
||||
beforeEach(() => {
|
||||
// Create a new mock client for each test to reset call history
|
||||
mockMcpClient = new (Client as any)({
|
||||
name: 'test-client',
|
||||
version: '0.0.1',
|
||||
}) as Mocked<Client>;
|
||||
vi.mocked(mockMcpClient.callTool).mockClear();
|
||||
});
|
||||
|
||||
afterEach(() => {
|
||||
vi.restoreAllMocks();
|
||||
});
|
||||
|
||||
describe('constructor', () => {
|
||||
it('should set properties correctly and augment description', () => {
|
||||
const tool = new DiscoveredMCPTool(
|
||||
mockMcpClient,
|
||||
toolName,
|
||||
baseDescription,
|
||||
inputSchema,
|
||||
serverToolName,
|
||||
);
|
||||
|
||||
expect(tool.name).toBe(toolName);
|
||||
expect(tool.schema.name).toBe(toolName);
|
||||
expect(tool.schema.description).toContain(baseDescription);
|
||||
expect(tool.schema.description).toContain('This MCP tool was discovered');
|
||||
// Corrected assertion for backticks and template literal
|
||||
expect(tool.schema.description).toContain(
|
||||
`tools/call\` method for tool name \`${toolName}\``,
|
||||
);
|
||||
expect(tool.schema.parameters).toEqual(inputSchema);
|
||||
expect(tool.serverToolName).toBe(serverToolName);
|
||||
expect(tool.timeout).toBeUndefined();
|
||||
});
|
||||
|
||||
it('should accept and store a custom timeout', () => {
|
||||
const customTimeout = 5000;
|
||||
const tool = new DiscoveredMCPTool(
|
||||
mockMcpClient,
|
||||
toolName,
|
||||
baseDescription,
|
||||
inputSchema,
|
||||
serverToolName,
|
||||
customTimeout,
|
||||
);
|
||||
expect(tool.timeout).toBe(customTimeout);
|
||||
});
|
||||
});
|
||||
|
||||
describe('execute', () => {
|
||||
it('should call mcpClient.callTool with correct parameters and default timeout', async () => {
|
||||
const tool = new DiscoveredMCPTool(
|
||||
mockMcpClient,
|
||||
toolName,
|
||||
baseDescription,
|
||||
inputSchema,
|
||||
serverToolName,
|
||||
);
|
||||
const params = { param: 'testValue' };
|
||||
const expectedMcpResult = { success: true, details: 'executed' };
|
||||
vi.mocked(mockMcpClient.callTool).mockResolvedValue(expectedMcpResult);
|
||||
|
||||
const result: ToolResult = await tool.execute(params);
|
||||
|
||||
expect(mockMcpClient.callTool).toHaveBeenCalledWith(
|
||||
{
|
||||
name: serverToolName,
|
||||
arguments: params,
|
||||
},
|
||||
undefined,
|
||||
{
|
||||
timeout: MCP_TOOL_DEFAULT_TIMEOUT_MSEC,
|
||||
},
|
||||
);
|
||||
const expectedOutput = JSON.stringify(expectedMcpResult, null, 2);
|
||||
expect(result.llmContent).toBe(expectedOutput);
|
||||
expect(result.returnDisplay).toBe(expectedOutput);
|
||||
});
|
||||
|
||||
it('should call mcpClient.callTool with custom timeout if provided', async () => {
|
||||
const customTimeout = 15000;
|
||||
const tool = new DiscoveredMCPTool(
|
||||
mockMcpClient,
|
||||
toolName,
|
||||
baseDescription,
|
||||
inputSchema,
|
||||
serverToolName,
|
||||
customTimeout,
|
||||
);
|
||||
const params = { param: 'anotherValue' };
|
||||
const expectedMcpResult = { result: 'done' };
|
||||
vi.mocked(mockMcpClient.callTool).mockResolvedValue(expectedMcpResult);
|
||||
|
||||
await tool.execute(params);
|
||||
|
||||
expect(mockMcpClient.callTool).toHaveBeenCalledWith(
|
||||
expect.anything(),
|
||||
undefined,
|
||||
{
|
||||
timeout: customTimeout,
|
||||
},
|
||||
);
|
||||
});
|
||||
|
||||
it('should propagate rejection if mcpClient.callTool rejects', async () => {
|
||||
const tool = new DiscoveredMCPTool(
|
||||
mockMcpClient,
|
||||
toolName,
|
||||
baseDescription,
|
||||
inputSchema,
|
||||
serverToolName,
|
||||
);
|
||||
const params = { param: 'failCase' };
|
||||
const expectedError = new Error('MCP call failed');
|
||||
vi.mocked(mockMcpClient.callTool).mockRejectedValue(expectedError);
|
||||
|
||||
await expect(tool.execute(params)).rejects.toThrow(expectedError);
|
||||
});
|
||||
});
|
||||
});
|
||||
|
|
@ -0,0 +1,49 @@
|
|||
/**
|
||||
* @license
|
||||
* Copyright 2025 Google LLC
|
||||
* SPDX-License-Identifier: Apache-2.0
|
||||
*/
|
||||
|
||||
import { Client } from '@modelcontextprotocol/sdk/client/index.js';
|
||||
import { BaseTool, ToolResult } from './tools.js';
|
||||
|
||||
type ToolParams = Record<string, unknown>;
|
||||
|
||||
export const MCP_TOOL_DEFAULT_TIMEOUT_MSEC = 10 * 60 * 1000; // default to 10 minutes
|
||||
|
||||
export class DiscoveredMCPTool extends BaseTool<ToolParams, ToolResult> {
|
||||
constructor(
|
||||
private readonly mcpClient: Client,
|
||||
readonly name: string,
|
||||
readonly description: string,
|
||||
readonly parameterSchema: Record<string, unknown>,
|
||||
readonly serverToolName: string,
|
||||
readonly timeout?: number,
|
||||
) {
|
||||
description += `
|
||||
|
||||
This MCP tool was discovered from a local MCP server using JSON RPC 2.0 over stdio transport protocol.
|
||||
When called, this tool will invoke the \`tools/call\` method for tool name \`${name}\`.
|
||||
MCP servers can be configured in project or user settings.
|
||||
Returns the MCP server response as a json string.
|
||||
`;
|
||||
super(name, name, description, parameterSchema);
|
||||
}
|
||||
|
||||
async execute(params: ToolParams): Promise<ToolResult> {
|
||||
const result = await this.mcpClient.callTool(
|
||||
{
|
||||
name: this.serverToolName,
|
||||
arguments: params,
|
||||
},
|
||||
undefined, // skip resultSchema to specify options (RequestOptions)
|
||||
{
|
||||
timeout: this.timeout ?? MCP_TOOL_DEFAULT_TIMEOUT_MSEC,
|
||||
},
|
||||
);
|
||||
return {
|
||||
llmContent: JSON.stringify(result, null, 2),
|
||||
returnDisplay: JSON.stringify(result, null, 2),
|
||||
};
|
||||
}
|
||||
}
|
||||
|
|
@ -14,11 +14,8 @@ import {
|
|||
afterEach,
|
||||
Mocked,
|
||||
} from 'vitest';
|
||||
import {
|
||||
ToolRegistry,
|
||||
DiscoveredTool,
|
||||
DiscoveredMCPTool,
|
||||
} from './tool-registry.js';
|
||||
import { ToolRegistry, DiscoveredTool } from './tool-registry.js';
|
||||
import { DiscoveredMCPTool } from './mcp-tool.js';
|
||||
import { Config } from '../config/config.js';
|
||||
import { BaseTool, ToolResult } from './tools.js';
|
||||
import { FunctionDeclaration } from '@google/genai';
|
||||
|
|
@ -347,7 +344,7 @@ describe('ToolRegistry', () => {
|
|||
toolRegistry = new ToolRegistry(config);
|
||||
});
|
||||
|
||||
it('should discover tools using discovery command', () => {
|
||||
it('should discover tools using discovery command', async () => {
|
||||
const discoveryCommand = 'my-discovery-command';
|
||||
mockConfigGetToolDiscoveryCommand.mockReturnValue(discoveryCommand);
|
||||
const mockToolDeclarations: FunctionDeclaration[] = [
|
||||
|
|
@ -366,7 +363,7 @@ describe('ToolRegistry', () => {
|
|||
),
|
||||
);
|
||||
|
||||
toolRegistry.discoverTools();
|
||||
await toolRegistry.discoverTools();
|
||||
|
||||
expect(execSync).toHaveBeenCalledWith(discoveryCommand);
|
||||
const discoveredTool = toolRegistry.getTool('discovered-tool-1');
|
||||
|
|
@ -376,7 +373,7 @@ describe('ToolRegistry', () => {
|
|||
expect(discoveredTool?.description).toContain(discoveryCommand);
|
||||
});
|
||||
|
||||
it('should remove previously discovered tools before discovering new ones', () => {
|
||||
it('should remove previously discovered tools before discovering new ones', async () => {
|
||||
const discoveryCommand = 'my-discovery-command';
|
||||
mockConfigGetToolDiscoveryCommand.mockReturnValue(discoveryCommand);
|
||||
mockExecSync.mockReturnValueOnce(
|
||||
|
|
@ -394,7 +391,7 @@ describe('ToolRegistry', () => {
|
|||
]),
|
||||
),
|
||||
);
|
||||
toolRegistry.discoverTools();
|
||||
await toolRegistry.discoverTools();
|
||||
expect(toolRegistry.getTool('old-discovered-tool')).toBeInstanceOf(
|
||||
DiscoveredTool,
|
||||
);
|
||||
|
|
@ -414,7 +411,7 @@ describe('ToolRegistry', () => {
|
|||
]),
|
||||
),
|
||||
);
|
||||
toolRegistry.discoverTools();
|
||||
await toolRegistry.discoverTools();
|
||||
expect(toolRegistry.getTool('old-discovered-tool')).toBeUndefined();
|
||||
expect(toolRegistry.getTool('new-discovered-tool')).toBeInstanceOf(
|
||||
DiscoveredTool,
|
||||
|
|
@ -457,8 +454,7 @@ describe('ToolRegistry', () => {
|
|||
});
|
||||
mockMcpClientInstance.connect.mockResolvedValue(undefined);
|
||||
|
||||
toolRegistry.discoverTools();
|
||||
await new Promise((resolve) => setTimeout(resolve, 100)); // Wait for async operations
|
||||
await toolRegistry.discoverTools();
|
||||
|
||||
expect(Client).toHaveBeenCalledTimes(1);
|
||||
expect(StdioClientTransport).toHaveBeenCalledWith({
|
||||
|
|
@ -511,8 +507,7 @@ describe('ToolRegistry', () => {
|
|||
});
|
||||
mockMcpClientInstance.connect.mockResolvedValue(undefined);
|
||||
|
||||
toolRegistry.discoverTools();
|
||||
await new Promise((resolve) => setTimeout(resolve, 100));
|
||||
await toolRegistry.discoverTools();
|
||||
|
||||
expect(Client).toHaveBeenCalledTimes(1);
|
||||
expect(StdioClientTransport).toHaveBeenCalledWith({
|
||||
|
|
@ -544,8 +539,7 @@ describe('ToolRegistry', () => {
|
|||
// Need to await the async IIFE within discoverTools.
|
||||
// Since discoverTools itself isn't async, we can't directly await it.
|
||||
// We'll check the console.error mock.
|
||||
toolRegistry.discoverTools();
|
||||
await new Promise((resolve) => setTimeout(resolve, 100)); // Wait for async operations
|
||||
await toolRegistry.discoverTools();
|
||||
|
||||
expect(console.error).toHaveBeenCalledWith(
|
||||
`failed to start or connect to MCP server 'failing-mcp' ${JSON.stringify({ command: 'fail-cmd' })}; \nError: Connection failed`,
|
||||
|
|
|
|||
|
|
@ -7,15 +7,11 @@
|
|||
import { FunctionDeclaration } from '@google/genai';
|
||||
import { Tool, ToolResult, BaseTool } from './tools.js';
|
||||
import { Config } from '../config/config.js';
|
||||
import { parse } from 'shell-quote';
|
||||
import { spawn, execSync } from 'node:child_process';
|
||||
// TODO: remove this dependency once MCP support is built into genai SDK
|
||||
import { Client } from '@modelcontextprotocol/sdk/client/index.js';
|
||||
import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
|
||||
import { SSEClientTransport } from '@modelcontextprotocol/sdk/client/sse.js';
|
||||
type ToolParams = Record<string, unknown>;
|
||||
import { discoverMcpTools } from './mcp-client.js';
|
||||
import { DiscoveredMCPTool } from './mcp-tool.js';
|
||||
|
||||
const MCP_TOOL_DEFAULT_TIMEOUT_MSEC = 10 * 60 * 1000; // default to 10 minutes
|
||||
type ToolParams = Record<string, unknown>;
|
||||
|
||||
export class DiscoveredTool extends BaseTool<ToolParams, ToolResult> {
|
||||
constructor(
|
||||
|
|
@ -95,43 +91,6 @@ Signal: Signal number or \`(none)\` if no signal was received.
|
|||
}
|
||||
}
|
||||
|
||||
export class DiscoveredMCPTool extends BaseTool<ToolParams, ToolResult> {
|
||||
constructor(
|
||||
private readonly mcpClient: Client,
|
||||
readonly name: string,
|
||||
readonly description: string,
|
||||
readonly parameterSchema: Record<string, unknown>,
|
||||
readonly serverToolName: string,
|
||||
readonly timeout?: number,
|
||||
) {
|
||||
description += `
|
||||
|
||||
This MCP tool was discovered from a local MCP server using JSON RPC 2.0 over stdio transport protocol.
|
||||
When called, this tool will invoke the \`tools/call\` method for tool name \`${name}\`.
|
||||
MCP servers can be configured in project or user settings.
|
||||
Returns the MCP server response as a json string.
|
||||
`;
|
||||
super(name, name, description, parameterSchema);
|
||||
}
|
||||
|
||||
async execute(params: ToolParams): Promise<ToolResult> {
|
||||
const result = await this.mcpClient.callTool(
|
||||
{
|
||||
name: this.serverToolName,
|
||||
arguments: params,
|
||||
},
|
||||
undefined, // skip resultSchema to specify options (RequestOptions)
|
||||
{
|
||||
timeout: this.timeout ?? MCP_TOOL_DEFAULT_TIMEOUT_MSEC,
|
||||
},
|
||||
);
|
||||
return {
|
||||
llmContent: JSON.stringify(result, null, 2),
|
||||
returnDisplay: JSON.stringify(result, null, 2),
|
||||
};
|
||||
}
|
||||
}
|
||||
|
||||
export class ToolRegistry {
|
||||
private tools: Map<string, Tool> = new Map();
|
||||
private config: Config;
|
||||
|
|
@ -158,11 +117,13 @@ export class ToolRegistry {
|
|||
* Discovers tools from project, if a discovery command is configured.
|
||||
* Can be called multiple times to update discovered tools.
|
||||
*/
|
||||
discoverTools(): void {
|
||||
async discoverTools(): Promise<void> {
|
||||
// remove any previously discovered tools
|
||||
for (const tool of this.tools.values()) {
|
||||
if (tool instanceof DiscoveredTool) {
|
||||
if (tool instanceof DiscoveredTool || tool instanceof DiscoveredMCPTool) {
|
||||
this.tools.delete(tool.name);
|
||||
} else {
|
||||
// Keep manually registered tools
|
||||
}
|
||||
}
|
||||
// discover tools using discovery command, if configured
|
||||
|
|
@ -186,106 +147,7 @@ export class ToolRegistry {
|
|||
}
|
||||
}
|
||||
// discover tools using MCP servers, if configured
|
||||
// convert mcpServerCommand (if any) to StdioServerParameters
|
||||
const mcpServers = this.config.getMcpServers() || {};
|
||||
|
||||
if (this.config.getMcpServerCommand()) {
|
||||
const cmd = this.config.getMcpServerCommand()!;
|
||||
const args = parse(cmd, process.env) as string[];
|
||||
if (args.some((arg) => typeof arg !== 'string')) {
|
||||
throw new Error('failed to parse mcpServerCommand: ' + cmd);
|
||||
}
|
||||
// use generic server name 'mcp'
|
||||
mcpServers['mcp'] = {
|
||||
command: args[0],
|
||||
args: args.slice(1),
|
||||
};
|
||||
}
|
||||
for (const [mcpServerName, mcpServerConfig] of Object.entries(mcpServers)) {
|
||||
(async () => {
|
||||
const mcpClient = new Client({
|
||||
name: 'mcp-client',
|
||||
version: '0.0.1',
|
||||
});
|
||||
let transport;
|
||||
if (mcpServerConfig.url) {
|
||||
// SSE transport if URL is provided
|
||||
transport = new SSEClientTransport(new URL(mcpServerConfig.url));
|
||||
} else if (mcpServerConfig.command) {
|
||||
// Stdio transport if command is provided
|
||||
transport = new StdioClientTransport({
|
||||
command: mcpServerConfig.command,
|
||||
args: mcpServerConfig.args || [],
|
||||
env: {
|
||||
...process.env,
|
||||
...(mcpServerConfig.env || {}),
|
||||
} as Record<string, string>,
|
||||
cwd: mcpServerConfig.cwd,
|
||||
stderr: 'pipe',
|
||||
});
|
||||
} else {
|
||||
console.error(
|
||||
`MCP server '${mcpServerName}' has invalid configuration: missing both url (for SSE) and command (for stdio). Skipping.`,
|
||||
);
|
||||
return;
|
||||
}
|
||||
try {
|
||||
await mcpClient.connect(transport);
|
||||
} catch (error) {
|
||||
console.error(
|
||||
`failed to start or connect to MCP server '${mcpServerName}' ` +
|
||||
`${JSON.stringify(mcpServerConfig)}; \n${error}`,
|
||||
);
|
||||
// Do not re-throw, let other MCP servers be discovered.
|
||||
return; // Exit this async IIFE if connection failed
|
||||
}
|
||||
mcpClient.onerror = (error) => {
|
||||
console.error('MCP ERROR', error.toString());
|
||||
};
|
||||
if (transport instanceof StdioClientTransport && !transport.stderr) {
|
||||
throw new Error('transport missing stderr stream');
|
||||
}
|
||||
if (transport instanceof StdioClientTransport) {
|
||||
transport.stderr!.on('data', (data) => {
|
||||
// filter out INFO messages logged for each request received
|
||||
if (!data.toString().includes('] INFO')) {
|
||||
console.debug('MCP STDERR', data.toString());
|
||||
}
|
||||
});
|
||||
}
|
||||
const result = await mcpClient.listTools();
|
||||
for (const tool of result.tools) {
|
||||
// Recursively remove additionalProperties and $schema from the inputSchema
|
||||
// eslint-disable-next-line @typescript-eslint/no-explicit-any -- This function recursively navigates a deeply nested and potentially heterogeneous JSON schema object. Using 'any' is a pragmatic choice here to avoid overly complex type definitions for all possible schema variations.
|
||||
const removeSchemaProps = (obj: any) => {
|
||||
if (typeof obj !== 'object' || obj === null) {
|
||||
return;
|
||||
}
|
||||
if (Array.isArray(obj)) {
|
||||
obj.forEach(removeSchemaProps);
|
||||
} else {
|
||||
delete obj.additionalProperties;
|
||||
delete obj.$schema;
|
||||
Object.values(obj).forEach(removeSchemaProps);
|
||||
}
|
||||
};
|
||||
removeSchemaProps(tool.inputSchema);
|
||||
|
||||
this.registerTool(
|
||||
new DiscoveredMCPTool(
|
||||
mcpClient,
|
||||
Object.keys(mcpServers).length > 1
|
||||
? mcpServerName + '__' + tool.name
|
||||
: tool.name,
|
||||
tool.description ?? '',
|
||||
tool.inputSchema,
|
||||
tool.name,
|
||||
mcpServerConfig.timeout,
|
||||
),
|
||||
);
|
||||
}
|
||||
})();
|
||||
}
|
||||
await discoverMcpTools(this.config, this);
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
|
|||
Loading…
Reference in New Issue