feat(mcp): add gemini mcp commands for add, remove and list (#5481)

packages/cli/src/commands/mcp.test.ts

@@ -0,0 +1,55 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi } from 'vitest';
+import { mcpCommand } from './mcp.js';
+import { type Argv } from 'yargs';
+import yargs from 'yargs';
+
+describe('mcp command', () => {
+  it('should have correct command definition', () => {
+    expect(mcpCommand.command).toBe('mcp');
+    expect(mcpCommand.describe).toBe('Manage MCP servers');
+    expect(typeof mcpCommand.builder).toBe('function');
+    expect(typeof mcpCommand.handler).toBe('function');
+  });
+
+  it('should have exactly one option (help flag)', () => {
+    // Test to ensure that the global 'gemini' flags are not added to the mcp command
+    const yargsInstance = yargs();
+    const builtYargs = mcpCommand.builder(yargsInstance);
+    const options = builtYargs.getOptions();
+
+    // Should have exactly 1 option (help flag)
+    expect(Object.keys(options.key).length).toBe(1);
+    expect(options.key).toHaveProperty('help');
+  });
+
+  it('should register add, remove, and list subcommands', () => {
+    const mockYargs = {
+      command: vi.fn().mockReturnThis(),
+      demandCommand: vi.fn().mockReturnThis(),
+      version: vi.fn().mockReturnThis(),
+    };
+
+    mcpCommand.builder(mockYargs as unknown as Argv);
+
+    expect(mockYargs.command).toHaveBeenCalledTimes(3);
+
+    // Verify that the specific subcommands are registered
+    const commandCalls = mockYargs.command.mock.calls;
+    const commandNames = commandCalls.map((call) => call[0].command);
+
+    expect(commandNames).toContain('add <name> <commandOrUrl> [args...]');
+    expect(commandNames).toContain('remove <name>');
+    expect(commandNames).toContain('list');
+
+    expect(mockYargs.demandCommand).toHaveBeenCalledWith(
+      1,
+      'You need at least one command before continuing.',
+    );
+  });
+});

packages/cli/src/commands/mcp.ts

@@ -0,0 +1,27 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+// File for 'gemini mcp' command
+import type { CommandModule, Argv } from 'yargs';
+import { addCommand } from './mcp/add.js';
+import { removeCommand } from './mcp/remove.js';
+import { listCommand } from './mcp/list.js';
+
+export const mcpCommand: CommandModule = {
+  command: 'mcp',
+  describe: 'Manage MCP servers',
+  builder: (yargs: Argv) =>
+    yargs
+      .command(addCommand)
+      .command(removeCommand)
+      .command(listCommand)
+      .demandCommand(1, 'You need at least one command before continuing.')
+      .version(false),
+  handler: () => {
+    // yargs will automatically show help if no subcommand is provided
+    // thanks to demandCommand(1) in the builder.
+  },
+};

packages/cli/src/commands/mcp/add.test.ts

@@ -0,0 +1,88 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import yargs from 'yargs';
+import { addCommand } from './add.js';
+import { loadSettings, SettingScope } from '../../config/settings.js';
+
+vi.mock('fs/promises', () => ({
+  readFile: vi.fn(),
+  writeFile: vi.fn(),
+}));
+
+vi.mock('../../config/settings.js', async () => {
+  const actual = await vi.importActual('../../config/settings.js');
+  return {
+    ...actual,
+    loadSettings: vi.fn(),
+  };
+});
+
+const mockedLoadSettings = loadSettings as vi.Mock;
+
+describe('mcp add command', () => {
+  let parser: yargs.Argv;
+  let mockSetValue: vi.Mock;
+
+  beforeEach(() => {
+    vi.resetAllMocks();
+    const yargsInstance = yargs([]).command(addCommand);
+    parser = yargsInstance;
+    mockSetValue = vi.fn();
+    mockedLoadSettings.mockReturnValue({
+      forScope: () => ({ settings: {} }),
+      setValue: mockSetValue,
+    });
+  });
+
+  it('should add a stdio server to project settings', async () => {
+    await parser.parseAsync(
+      'add my-server /path/to/server arg1 arg2 -e FOO=bar',
+    );
+
+    expect(mockSetValue).toHaveBeenCalledWith(
+      SettingScope.Workspace,
+      'mcpServers',
+      {
+        'my-server': {
+          command: '/path/to/server',
+          args: ['arg1', 'arg2'],
+          env: { FOO: 'bar' },
+        },
+      },
+    );
+  });
+
+  it('should add an sse server to user settings', async () => {
+    await parser.parseAsync(
+      'add --transport sse sse-server https://example.com/sse-endpoint --scope user -H "X-API-Key: your-key"',
+    );
+
+    expect(mockSetValue).toHaveBeenCalledWith(SettingScope.User, 'mcpServers', {
+      'sse-server': {
+        url: 'https://example.com/sse-endpoint',
+        headers: { 'X-API-Key': 'your-key' },
+      },
+    });
+  });
+
+  it('should add an http server to project settings', async () => {
+    await parser.parseAsync(
+      'add --transport http http-server https://example.com/mcp -H "Authorization: Bearer your-token"',
+    );
+
+    expect(mockSetValue).toHaveBeenCalledWith(
+      SettingScope.Workspace,
+      'mcpServers',
+      {
+        'http-server': {
+          httpUrl: 'https://example.com/mcp',
+          headers: { Authorization: 'Bearer your-token' },
+        },
+      },
+    );
+  });
+});

packages/cli/src/commands/mcp/add.ts

@@ -0,0 +1,211 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+// File for 'gemini mcp add' command
+import type { CommandModule } from 'yargs';
+import { loadSettings, SettingScope } from '../../config/settings.js';
+import { MCPServerConfig } from '@google/gemini-cli-core';
+
+async function addMcpServer(
+  name: string,
+  commandOrUrl: string,
+  args: Array<string | number> | undefined,
+  options: {
+    scope: string;
+    transport: string;
+    env: string[] | undefined;
+    header: string[] | undefined;
+    timeout?: number;
+    trust?: boolean;
+    description?: string;
+    includeTools?: string[];
+    excludeTools?: string[];
+  },
+) {
+  const {
+    scope,
+    transport,
+    env,
+    header,
+    timeout,
+    trust,
+    description,
+    includeTools,
+    excludeTools,
+  } = options;
+  const settingsScope =
+    scope === 'user' ? SettingScope.User : SettingScope.Workspace;
+  const settings = loadSettings(process.cwd());
+
+  let newServer: Partial<MCPServerConfig> = {};
+
+  const headers = header?.reduce(
+    (acc, curr) => {
+      const [key, ...valueParts] = curr.split(':');
+      const value = valueParts.join(':').trim();
+      if (key.trim() && value) {
+        acc[key.trim()] = value;
+      }
+      return acc;
+    },
+    {} as Record<string, string>,
+  );
+
+  switch (transport) {
+    case 'sse':
+      newServer = {
+        url: commandOrUrl,
+        headers,
+        timeout,
+        trust,
+        description,
+        includeTools,
+        excludeTools,
+      };
+      break;
+    case 'http':
+      newServer = {
+        httpUrl: commandOrUrl,
+        headers,
+        timeout,
+        trust,
+        description,
+        includeTools,
+        excludeTools,
+      };
+      break;
+    case 'stdio':
+    default:
+      newServer = {
+        command: commandOrUrl,
+        args: args?.map(String),
+        env: env?.reduce(
+          (acc, curr) => {
+            const [key, value] = curr.split('=');
+            if (key && value) {
+              acc[key] = value;
+            }
+            return acc;
+          },
+          {} as Record<string, string>,
+        ),
+        timeout,
+        trust,
+        description,
+        includeTools,
+        excludeTools,
+      };
+      break;
+  }
+
+  const existingSettings = settings.forScope(settingsScope).settings;
+  const mcpServers = existingSettings.mcpServers || {};
+
+  const isExistingServer = !!mcpServers[name];
+  if (isExistingServer) {
+    console.log(
+      `MCP server "${name}" is already configured within ${scope} settings.`,
+    );
+  }
+
+  mcpServers[name] = newServer as MCPServerConfig;
+
+  settings.setValue(settingsScope, 'mcpServers', mcpServers);
+
+  if (isExistingServer) {
+    console.log(`MCP server "${name}" updated in ${scope} settings.`);
+  } else {
+    console.log(
+      `MCP server "${name}" added to ${scope} settings. (${transport})`,
+    );
+  }
+}
+
+export const addCommand: CommandModule = {
+  command: 'add <name> <commandOrUrl> [args...]',
+  describe: 'Add a server',
+  builder: (yargs) =>
+    yargs
+      .usage('Usage: gemini mcp add [options] <name> <commandOrUrl> [args...]')
+      .positional('name', {
+        describe: 'Name of the server',
+        type: 'string',
+        demandOption: true,
+      })
+      .positional('commandOrUrl', {
+        describe: 'Command (stdio) or URL (sse, http)',
+        type: 'string',
+        demandOption: true,
+      })
+      .option('scope', {
+        alias: 's',
+        describe: 'Configuration scope (user or project)',
+        type: 'string',
+        default: 'project',
+        choices: ['user', 'project'],
+      })
+      .option('transport', {
+        alias: 't',
+        describe: 'Transport type (stdio, sse, http)',
+        type: 'string',
+        default: 'stdio',
+        choices: ['stdio', 'sse', 'http'],
+      })
+      .option('env', {
+        alias: 'e',
+        describe: 'Set environment variables (e.g. -e KEY=value)',
+        type: 'array',
+        string: true,
+      })
+      .option('header', {
+        alias: 'H',
+        describe:
+          'Set HTTP headers for SSE and HTTP transports (e.g. -H "X-Api-Key: abc123" -H "Authorization: Bearer abc123")',
+        type: 'array',
+        string: true,
+      })
+      .option('timeout', {
+        describe: 'Set connection timeout in milliseconds',
+        type: 'number',
+      })
+      .option('trust', {
+        describe:
+          'Trust the server (bypass all tool call confirmation prompts)',
+        type: 'boolean',
+      })
+      .option('description', {
+        describe: 'Set the description for the server',
+        type: 'string',
+      })
+      .option('include-tools', {
+        describe: 'A comma-separated list of tools to include',
+        type: 'array',
+        string: true,
+      })
+      .option('exclude-tools', {
+        describe: 'A comma-separated list of tools to exclude',
+        type: 'array',
+        string: true,
+      }),
+  handler: async (argv) => {
+    await addMcpServer(
+      argv.name as string,
+      argv.commandOrUrl as string,
+      argv.args as Array<string | number>,
+      {
+        scope: argv.scope as string,
+        transport: argv.transport as string,
+        env: argv.env as string[],
+        header: argv.header as string[],
+        timeout: argv.timeout as number | undefined,
+        trust: argv.trust as boolean | undefined,
+        description: argv.description as string | undefined,
+        includeTools: argv.includeTools as string[] | undefined,
+        excludeTools: argv.excludeTools as string[] | undefined,
+      },
+    );
+  },
+};

packages/cli/src/commands/mcp/list.test.ts

@@ -0,0 +1,154 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { vi, describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { listMcpServers } from './list.js';
+import { loadSettings } from '../../config/settings.js';
+import { loadExtensions } from '../../config/extension.js';
+import { createTransport } from '@google/gemini-cli-core';
+import { Client } from '@modelcontextprotocol/sdk/client/index.js';
+
+vi.mock('../../config/settings.js');
+vi.mock('../../config/extension.js');
+vi.mock('@google/gemini-cli-core');
+vi.mock('@modelcontextprotocol/sdk/client/index.js');
+
+const mockedLoadSettings = loadSettings as vi.Mock;
+const mockedLoadExtensions = loadExtensions as vi.Mock;
+const mockedCreateTransport = createTransport as vi.Mock;
+const MockedClient = Client as vi.Mock;
+
+interface MockClient {
+  connect: vi.Mock;
+  ping: vi.Mock;
+  close: vi.Mock;
+}
+
+interface MockTransport {
+  close: vi.Mock;
+}
+
+describe('mcp list command', () => {
+  let consoleSpy: vi.SpyInstance;
+  let mockClient: MockClient;
+  let mockTransport: MockTransport;
+
+  beforeEach(() => {
+    vi.resetAllMocks();
+
+    consoleSpy = vi.spyOn(console, 'log').mockImplementation(() => {});
+
+    mockTransport = { close: vi.fn() };
+    mockClient = {
+      connect: vi.fn(),
+      ping: vi.fn(),
+      close: vi.fn(),
+    };
+
+    MockedClient.mockImplementation(() => mockClient);
+    mockedCreateTransport.mockResolvedValue(mockTransport);
+    mockedLoadExtensions.mockReturnValue([]);
+  });
+
+  afterEach(() => {
+    consoleSpy.mockRestore();
+  });
+
+  it('should display message when no servers configured', async () => {
+    mockedLoadSettings.mockReturnValue({ merged: { mcpServers: {} } });
+
+    await listMcpServers();
+
+    expect(consoleSpy).toHaveBeenCalledWith('No MCP servers configured.');
+  });
+
+  it('should display different server types with connected status', async () => {
+    mockedLoadSettings.mockReturnValue({
+      merged: {
+        mcpServers: {
+          'stdio-server': { command: '/path/to/server', args: ['arg1'] },
+          'sse-server': { url: 'https://example.com/sse' },
+          'http-server': { httpUrl: 'https://example.com/http' },
+        },
+      },
+    });
+
+    mockClient.connect.mockResolvedValue(undefined);
+    mockClient.ping.mockResolvedValue(undefined);
+
+    await listMcpServers();
+
+    expect(consoleSpy).toHaveBeenCalledWith('Configured MCP servers:\n');
+    expect(consoleSpy).toHaveBeenCalledWith(
+      expect.stringContaining(
+        'stdio-server: /path/to/server arg1 (stdio) - Connected',
+      ),
+    );
+    expect(consoleSpy).toHaveBeenCalledWith(
+      expect.stringContaining(
+        'sse-server: https://example.com/sse (sse) - Connected',
+      ),
+    );
+    expect(consoleSpy).toHaveBeenCalledWith(
+      expect.stringContaining(
+        'http-server: https://example.com/http (http) - Connected',
+      ),
+    );
+  });
+
+  it('should display disconnected status when connection fails', async () => {
+    mockedLoadSettings.mockReturnValue({
+      merged: {
+        mcpServers: {
+          'test-server': { command: '/test/server' },
+        },
+      },
+    });
+
+    mockClient.connect.mockRejectedValue(new Error('Connection failed'));
+
+    await listMcpServers();
+
+    expect(consoleSpy).toHaveBeenCalledWith(
+      expect.stringContaining(
+        'test-server: /test/server  (stdio) - Disconnected',
+      ),
+    );
+  });
+
+  it('should merge extension servers with config servers', async () => {
+    mockedLoadSettings.mockReturnValue({
+      merged: {
+        mcpServers: { 'config-server': { command: '/config/server' } },
+      },
+    });
+
+    mockedLoadExtensions.mockReturnValue([
+      {
+        config: {
+          name: 'test-extension',
+          mcpServers: { 'extension-server': { command: '/ext/server' } },
+        },
+      },
+    ]);
+
+    mockClient.connect.mockResolvedValue(undefined);
+    mockClient.ping.mockResolvedValue(undefined);
+
+    await listMcpServers();
+
+    expect(consoleSpy).toHaveBeenCalledWith(
+      expect.stringContaining(
+        'config-server: /config/server  (stdio) - Connected',
+      ),
+    );
+    expect(consoleSpy).toHaveBeenCalledWith(
+      expect.stringContaining(
+        'extension-server: /ext/server  (stdio) - Connected',
+      ),
+    );
+  });
+});

packages/cli/src/commands/mcp/list.ts

@@ -0,0 +1,139 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+// File for 'gemini mcp list' command
+import type { CommandModule } from 'yargs';
+import { loadSettings } from '../../config/settings.js';
+import {
+  MCPServerConfig,
+  MCPServerStatus,
+  createTransport,
+} from '@google/gemini-cli-core';
+import { Client } from '@modelcontextprotocol/sdk/client/index.js';
+import { loadExtensions } from '../../config/extension.js';
+
+const COLOR_GREEN = '\u001b[32m';
+const COLOR_YELLOW = '\u001b[33m';
+const COLOR_RED = '\u001b[31m';
+const RESET_COLOR = '\u001b[0m';
+
+async function getMcpServersFromConfig(): Promise<
+  Record<string, MCPServerConfig>
+> {
+  const settings = loadSettings(process.cwd());
+  const extensions = loadExtensions(process.cwd());
+  const mcpServers = { ...(settings.merged.mcpServers || {}) };
+  for (const extension of extensions) {
+    Object.entries(extension.config.mcpServers || {}).forEach(
+      ([key, server]) => {
+        if (mcpServers[key]) {
+          return;
+        }
+        mcpServers[key] = {
+          ...server,
+          extensionName: extension.config.name,
+        };
+      },
+    );
+  }
+  return mcpServers;
+}
+
+async function testMCPConnection(
+  serverName: string,
+  config: MCPServerConfig,
+): Promise<MCPServerStatus> {
+  const client = new Client({
+    name: 'mcp-test-client',
+    version: '0.0.1',
+  });
+
+  let transport;
+  try {
+    // Use the same transport creation logic as core
+    transport = await createTransport(serverName, config, false);
+  } catch (_error) {
+    await client.close();
+    return MCPServerStatus.DISCONNECTED;
+  }
+
+  try {
+    // Attempt actual MCP connection with short timeout
+    await client.connect(transport, { timeout: 5000 }); // 5s timeout
+
+    // Test basic MCP protocol by pinging the server
+    await client.ping();
+
+    await client.close();
+    return MCPServerStatus.CONNECTED;
+  } catch (_error) {
+    await transport.close();
+    return MCPServerStatus.DISCONNECTED;
+  }
+}
+
+async function getServerStatus(
+  serverName: string,
+  server: MCPServerConfig,
+): Promise<MCPServerStatus> {
+  // Test all server types by attempting actual connection
+  return await testMCPConnection(serverName, server);
+}
+
+export async function listMcpServers(): Promise<void> {
+  const mcpServers = await getMcpServersFromConfig();
+  const serverNames = Object.keys(mcpServers);
+
+  if (serverNames.length === 0) {
+    console.log('No MCP servers configured.');
+    return;
+  }
+
+  console.log('Configured MCP servers:\n');
+
+  for (const serverName of serverNames) {
+    const server = mcpServers[serverName];
+
+    const status = await getServerStatus(serverName, server);
+
+    let statusIndicator = '';
+    let statusText = '';
+    switch (status) {
+      case MCPServerStatus.CONNECTED:
+        statusIndicator = COLOR_GREEN + '✓' + RESET_COLOR;
+        statusText = 'Connected';
+        break;
+      case MCPServerStatus.CONNECTING:
+        statusIndicator = COLOR_YELLOW + '…' + RESET_COLOR;
+        statusText = 'Connecting';
+        break;
+      case MCPServerStatus.DISCONNECTED:
+      default:
+        statusIndicator = COLOR_RED + '✗' + RESET_COLOR;
+        statusText = 'Disconnected';
+        break;
+    }
+
+    let serverInfo = `${serverName}: `;
+    if (server.httpUrl) {
+      serverInfo += `${server.httpUrl} (http)`;
+    } else if (server.url) {
+      serverInfo += `${server.url} (sse)`;
+    } else if (server.command) {
+      serverInfo += `${server.command} ${server.args?.join(' ') || ''} (stdio)`;
+    }
+
+    console.log(`${statusIndicator} ${serverInfo} - ${statusText}`);
+  }
+}
+
+export const listCommand: CommandModule = {
+  command: 'list',
+  describe: 'List all configured MCP servers',
+  handler: async () => {
+    await listMcpServers();
+  },
+};

packages/cli/src/commands/mcp/remove.test.ts

@@ -0,0 +1,69 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { vi, describe, it, expect, beforeEach } from 'vitest';
+import yargs from 'yargs';
+import { loadSettings, SettingScope } from '../../config/settings.js';
+import { removeCommand } from './remove.js';
+
+vi.mock('fs/promises', () => ({
+  readFile: vi.fn(),
+  writeFile: vi.fn(),
+}));
+
+vi.mock('../../config/settings.js', async () => {
+  const actual = await vi.importActual('../../config/settings.js');
+  return {
+    ...actual,
+    loadSettings: vi.fn(),
+  };
+});
+
+const mockedLoadSettings = loadSettings as vi.Mock;
+
+describe('mcp remove command', () => {
+  let parser: yargs.Argv;
+  let mockSetValue: vi.Mock;
+  let mockSettings: Record<string, unknown>;
+
+  beforeEach(() => {
+    vi.resetAllMocks();
+    const yargsInstance = yargs([]).command(removeCommand);
+    parser = yargsInstance;
+    mockSetValue = vi.fn();
+    mockSettings = {
+      mcpServers: {
+        'test-server': {
+          command: 'echo "hello"',
+        },
+      },
+    };
+    mockedLoadSettings.mockReturnValue({
+      forScope: () => ({ settings: mockSettings }),
+      setValue: mockSetValue,
+    });
+  });
+
+  it('should remove a server from project settings', async () => {
+    await parser.parseAsync('remove test-server');
+
+    expect(mockSetValue).toHaveBeenCalledWith(
+      SettingScope.Workspace,
+      'mcpServers',
+      {},
+    );
+  });
+
+  it('should show a message if server not found', async () => {
+    const consoleSpy = vi.spyOn(console, 'log').mockImplementation(() => {});
+    await parser.parseAsync('remove non-existent-server');
+
+    expect(mockSetValue).not.toHaveBeenCalled();
+    expect(consoleSpy).toHaveBeenCalledWith(
+      'Server "non-existent-server" not found in project settings.',
+    );
+  });
+});

packages/cli/src/commands/mcp/remove.ts

@@ -0,0 +1,60 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+// File for 'gemini mcp remove' command
+import type { CommandModule } from 'yargs';
+import { loadSettings, SettingScope } from '../../config/settings.js';
+
+async function removeMcpServer(
+  name: string,
+  options: {
+    scope: string;
+  },
+) {
+  const { scope } = options;
+  const settingsScope =
+    scope === 'user' ? SettingScope.User : SettingScope.Workspace;
+  const settings = loadSettings(process.cwd());
+
+  const existingSettings = settings.forScope(settingsScope).settings;
+  const mcpServers = existingSettings.mcpServers || {};
+
+  if (!mcpServers[name]) {
+    console.log(`Server "${name}" not found in ${scope} settings.`);
+    return;
+  }
+
+  delete mcpServers[name];
+
+  settings.setValue(settingsScope, 'mcpServers', mcpServers);
+
+  console.log(`Server "${name}" removed from ${scope} settings.`);
+}
+
+export const removeCommand: CommandModule = {
+  command: 'remove <name>',
+  describe: 'Remove a server',
+  builder: (yargs) =>
+    yargs
+      .usage('Usage: gemini mcp remove [options] <name>')
+      .positional('name', {
+        describe: 'Name of the server',
+        type: 'string',
+        demandOption: true,
+      })
+      .option('scope', {
+        alias: 's',
+        describe: 'Configuration scope (user or project)',
+        type: 'string',
+        default: 'project',
+        choices: ['user', 'project'],
+      }),
+  handler: async (argv) => {
+    await removeMcpServer(argv.name as string, {
+      scope: argv.scope as string,
+    });
+  },
+};