d74c0f581b
- 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
371 lines
13 KiB
TypeScript
371 lines
13 KiB
TypeScript
/**
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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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