Gmail MCP Server

Instructions

Implementation Reference

• src/index.ts:850-858 (registration)

  Registration of the 'get_pop' MCP tool. The inline handler function executes the tool logic by calling the shared handleTool helper, which authenticates via OAuth2 and invokes the Gmail API to retrieve POP settings for the user. No input parameters are required (empty schema).
  server.tool("get_pop", "Gets POP settings", {}, async () => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.settings.getPop({ userId: 'me' }) return formatResponse(data) }) }
• src/index.ts:853-858 (handler)

  The handler function for the 'get_pop' tool. It uses handleTool to perform OAuth2 validation and call gmail.users.settings.getPop API.
  async () => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.settings.getPop({ userId: 'me' }) return formatResponse(data) }) }
• src/index.ts:50-66 (helper)

  Shared helper function used by 'get_pop' (and other tools) to handle authentication, create Gmail client, execute the API call, and handle errors.
  const handleTool = async (queryConfig: Record<string, any> | undefined, apiCall: (gmail: gmail_v1.Gmail) => Promise<any>) => { try { const oauth2Client = queryConfig ? createOAuth2Client(queryConfig) : defaultOAuth2Client if (!oauth2Client) throw new Error('OAuth2 client could not be created, please check your credentials') const credentialsAreValid = await validateCredentials(oauth2Client) if (!credentialsAreValid) throw new Error('OAuth2 credentials are invalid, please re-authenticate') const gmailClient = queryConfig ? google.gmail({ version: 'v1', auth: oauth2Client }) : defaultGmailClient if (!gmailClient) throw new Error('Gmail client could not be created, please check your credentials') const result = await apiCall(gmailClient) return result } catch (error: any) { return `Tool execution failed: ${error.message}` } }
• src/index.ts:48-48 (helper)

  Helper function to format API responses for MCP tool output.
  const formatResponse = (response: any) => ({ content: [{ type: "text", text: JSON.stringify(response) }] })