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

/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

// File for 'gemini mcp list' command
import type { CommandModule } from 'yargs';
import {
  type MergedSettings,
  loadSettings,
  type LoadedSettings,
} from '../../config/settings.js';
import {
  MCPServerStatus,
  createTransport,
  debugLogger,
  applyAdminAllowlist,
  getAdminBlockedMcpServersMessage,
} from '@google/gemini-cli-core';
import type { MCPServerConfig } from '@google/gemini-cli-core';
import { Client } from '@modelcontextprotocol/sdk/client/index.js';
import { ExtensionManager } from '../../config/extension-manager.js';
import {
  canLoadServer,
  McpServerEnablementManager,
} from '../../config/mcp/index.js';
import { requestConsentNonInteractive } from '../../config/extensions/consent.js';
import { promptForSetting } from '../../config/extensions/extensionSettings.js';
import { exitCli } from '../utils.js';
import chalk from 'chalk';

export async function getMcpServersFromConfig(
  settings?: MergedSettings,
): Promise<{
  mcpServers: Record<string, MCPServerConfig>;
  blockedServerNames: string[];
}> {
  if (!settings) {
    settings = loadSettings().merged;
  }

  const extensionManager = new ExtensionManager({
    settings,
    workspaceDir: process.cwd(),
    requestConsent: requestConsentNonInteractive,
    requestSetting: promptForSetting,
  });
  const extensions = await extensionManager.loadExtensions();
  const mcpServers = { ...settings.mcpServers };
  for (const extension of extensions) {
    Object.entries(extension.mcpServers || {}).forEach(([key, server]) => {
      if (mcpServers[key]) {
        return;
      }
      mcpServers[key] = {
        // eslint-disable-next-line @typescript-eslint/no-misused-spread
        ...server,
        extension,
      };
    });
  }

  const adminAllowlist = settings.admin?.mcp?.config;
  const filteredResult = applyAdminAllowlist(mcpServers, adminAllowlist);

  return filteredResult;
}

const MCP_LIST_DEFAULT_TIMEOUT_MSEC = 5000;

async function testMCPConnection(
  serverName: string,
  config: MCPServerConfig,
  isTrusted: boolean,
  activeSettings: MergedSettings,
): Promise<MCPServerStatus> {
  // SECURITY: Only test connection if workspace is trusted or if it's a remote server.
  // stdio servers execute local commands and must never run in untrusted workspaces.
  const isStdio = !!config.command;
  if (isStdio && !isTrusted) {
    return MCPServerStatus.DISCONNECTED;
  }

  const client = new Client({
    name: 'mcp-test-client',
    version: '0.0.1',
  });

  const mcpContext = {
    sanitizationConfig: {
      enableEnvironmentVariableRedaction: true,
      allowedEnvironmentVariables: [],
      blockedEnvironmentVariables: activeSettings.advanced.excludedEnvVars,
    },
    emitMcpDiagnostic: (
      severity: 'info' | 'warning' | 'error',
      message: string,
      error?: unknown,
      serverName?: string,
    ) => {
      // In non-interactive list, we log everything through debugLogger for consistency
      if (severity === 'error') {
        debugLogger.error(
          chalk.red(`Error${serverName ? ` (${serverName})` : ''}: ${message}`),
          error,
        );
      } else if (severity === 'warning') {
        debugLogger.warn(
          chalk.yellow(
            `Warning${serverName ? ` (${serverName})` : ''}: ${message}`,
          ),
          error,
        );
      } else {
        debugLogger.log(message, error);
      }
    },
    isTrustedFolder: () => isTrusted,
  };

  let transport;
  try {
    // Use the same transport creation logic as core
    transport = await createTransport(serverName, config, false, mcpContext);
  } catch {
    await client.close();
    return MCPServerStatus.DISCONNECTED;
  }

  try {
    // Attempt actual MCP connection with timeout from config or default to 5s.
    // We use a short default for the list command to keep it responsive.
    const timeout = config.timeout ?? MCP_LIST_DEFAULT_TIMEOUT_MSEC;
    await client.connect(transport, { timeout });

    // Test basic MCP protocol by pinging the server.
    // Ping is optional per MCP spec - some servers (e.g. Google first-party)
    // don't implement it. A successful connect() is sufficient proof of connectivity.
    try {
      await client.ping({ timeout });
    } catch (e) {
      debugLogger.debug(
        `MCP ping failed for ${serverName}, but connect succeeded:`,
        e,
      );
    }

    await client.close();
    return MCPServerStatus.CONNECTED;
  } catch {
    await transport.close();
    return MCPServerStatus.DISCONNECTED;
  }
}

async function getServerStatus(
  serverName: string,
  server: MCPServerConfig,
  isTrusted: boolean,
  activeSettings: MergedSettings,
  consolidatedExcluded: string[],
  consolidatedAllowed: string[] | undefined,
): Promise<MCPServerStatus> {
  const mcpEnablementManager = McpServerEnablementManager.getInstance();

  const loadResult = await canLoadServer(serverName, {
    adminMcpEnabled: activeSettings.admin?.mcp?.enabled ?? true,
    allowedList: consolidatedAllowed,
    excludedList:
      consolidatedExcluded.length > 0 ? consolidatedExcluded : undefined,
    enablement: mcpEnablementManager.getEnablementCallbacks(),
  });

  if (!loadResult.allowed) {
    if (
      loadResult.blockType === 'admin' ||
      loadResult.blockType === 'allowlist' ||
      loadResult.blockType === 'excludelist'
    ) {
      return MCPServerStatus.BLOCKED;
    }
    return MCPServerStatus.DISABLED;
  }

  if (!isTrusted) {
    return MCPServerStatus.DISABLED;
  }

  // Test all server types by attempting actual connection
  return testMCPConnection(serverName, server, isTrusted, activeSettings);
}

export async function listMcpServers(
  loadedSettingsArg?: LoadedSettings,
): Promise<void> {
  const loadedSettings = loadedSettingsArg ?? loadSettings();
  const activeSettings = loadedSettings.merged;

  // If the folder is untrusted, we want to show all configured servers (including
  // project-scoped ones) as disabled.
  const allSettings = !loadedSettings.isTrusted
    ? loadedSettings.getMergedSettingsAsIfTrusted()
    : activeSettings;

  const { mcpServers, blockedServerNames } =
    await getMcpServersFromConfig(allSettings);
  const serverNames = Object.keys(mcpServers);

  if (blockedServerNames.length > 0) {
    const message = getAdminBlockedMcpServersMessage(
      blockedServerNames,
      undefined,
    );
    debugLogger.log(chalk.yellow(message + '\n'));
  }

  if (serverNames.length === 0) {
    if (blockedServerNames.length === 0) {
      debugLogger.log('No MCP servers configured.');
    }
    return;
  }

  if (!loadedSettings.isTrusted) {
    debugLogger.log(
      chalk.yellow(
        'Warning: MCP servers are configured but disabled because this folder is untrusted.\n' +
          'User-level servers are also suppressed in untrusted folders to prevent accidental side-effects.\n',
      ),
    );
  }

  const consolidatedExcluded =
    loadedSettings.getConsolidatedExcludedMcpServers();
  const consolidatedAllowed = loadedSettings.getConsolidatedAllowedMcpServers();

  debugLogger.log('Configured MCP servers:\n');

  for (const serverName of serverNames) {
    const server = mcpServers[serverName];

    const status = await getServerStatus(
      serverName,
      server,
      loadedSettings.isTrusted,
      activeSettings,
      consolidatedExcluded,
      consolidatedAllowed,
    );

    let statusIndicator = '';
    let statusText = '';
    switch (status) {
      case MCPServerStatus.CONNECTED:
        statusIndicator = chalk.green('✓');
        statusText = 'Connected';
        break;
      case MCPServerStatus.CONNECTING:
        statusIndicator = chalk.yellow('…');
        statusText = 'Connecting';
        break;
      case MCPServerStatus.BLOCKED:
        statusIndicator = chalk.red('⛔');
        statusText = 'Blocked';
        break;
      case MCPServerStatus.DISABLED:
        statusIndicator = chalk.gray('○');
        statusText = 'Disabled';
        break;
      case MCPServerStatus.DISCONNECTED:
      default:
        statusIndicator = chalk.red('✗');
        statusText = 'Disconnected';
        break;
    }

    let serverInfo =
      serverName +
      (server.extension?.name ? ` (from ${server.extension.name})` : '') +
      ': ';
    if (server.httpUrl) {
      serverInfo += `${server.httpUrl} (http)`;
    } else if (server.url) {
      const type = server.type || 'http';
      serverInfo += `${server.url} (${type})`;
    } else if (server.command) {
      serverInfo += `${server.command} ${server.args?.join(' ') || ''} (stdio)`;
    }

    debugLogger.log(`${statusIndicator} ${serverInfo} - ${statusText}`);
  }
}

interface ListArgs {
  loadedSettings?: LoadedSettings;
}

export const listCommand: CommandModule<object, ListArgs> = {
  command: 'list',
  describe: 'List all configured MCP servers',
  handler: async (argv) => {
    await listMcpServers(argv.loadedSettings);
    await exitCli();
  },
};