Gmail MCP Server

Instructions

Implementation Reference

• src/index.ts:1157-1166 (registration)

  Registration of the 'list_send_as' MCP tool, including schema (empty, no params) and inline handler that lists send-as aliases using Gmail users.settings.sendAs.list API.
  server.tool("list_send_as", "Lists the send-as aliases for the specified account", {}, async () => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.settings.sendAs.list({ userId: 'me' }) return formatResponse(data) }) } )
• src/index.ts:1160-1165 (handler)

  The handler function for 'list_send_as' tool: invokes handleTool to authenticate and call Gmail API's users.settings.sendAs.list with userId 'me', formats response.
  async () => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.settings.sendAs.list({ userId: 'me' }) return formatResponse(data) }) }
• src/index.ts:50-66 (helper)

  Shared helper function used by all Gmail tools, including list_send_as, to handle OAuth2 authentication, credential validation, Gmail client creation, and API call execution.
  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:48-49 (helper)

  Helper to format API responses as MCP content blocks with JSON stringified text.
  const formatResponse = (response: any) => ({ content: [{ type: "text", text: JSON.stringify(response) }] })