Gmail MCP Server

Instructions

Implementation Reference

• src/index.ts:1089-1100 (registration)

  Registration of the 'get_forwarding_address' tool including schema definition and inline handler function that calls the Gmail API to get the forwarding address.
  server.tool("get_forwarding_address", "Gets the specified forwarding address", { forwardingEmail: z.string().describe("The forwarding address to be retrieved") }, async (params) => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.settings.forwardingAddresses.get({ userId: 'me', forwardingEmail: params.forwardingEmail }) return formatResponse(data) }) } )
• src/index.ts:1094-1099 (handler)

  Inline handler implementation for get_forwarding_address tool. Uses handleTool helper to authenticate and call Gmail API's users.settings.forwardingAddresses.get method.
  async (params) => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.settings.forwardingAddresses.get({ userId: 'me', forwardingEmail: params.forwardingEmail }) return formatResponse(data) }) }
• src/index.ts:1091-1093 (schema)

  Input schema for get_forwarding_address tool requiring a single 'forwardingEmail' string parameter.
  { forwardingEmail: z.string().describe("The forwarding address to be retrieved") },
• src/index.ts:50-66 (helper)

  General helper function used by all tools, including get_forwarding_address, to handle OAuth2 authentication and execute the Gmail API call.
  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 into MCP-compatible content structure, used by get_forwarding_address handler.
  const formatResponse = (response: any) => ({ content: [{ type: "text", text: JSON.stringify(response) }] })