Gmail MCP Server

Instructions

Implementation Reference

• src/index.ts:987-996 (handler)

  The handler function for the 'list_delegates' tool. It uses handleTool to authenticate and calls the Gmail API gmail.users.settings.delegates.list to retrieve the list of delegates for the user's account, then formats the response.
  server.tool("list_delegates", "Lists the delegates for the specified account", {}, async () => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.settings.delegates.list({ userId: 'me' }) return formatResponse(data) }) } )
• src/index.ts:987-996 (registration)

  Registration of the 'list_delegates' tool on the MCP server using server.tool, including description, empty input schema, and inline handler.
  server.tool("list_delegates", "Lists the delegates for the specified account", {}, async () => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.settings.delegates.list({ userId: 'me' }) return formatResponse(data) }) } )
• src/index.ts:989-989 (schema)

  Input schema for list_delegates tool: empty object, indicating no parameters required.
  {},
• src/index.ts:50-66 (helper)

  Shared helper function handleTool used by list_delegates (and other tools) to handle OAuth2 authentication, client creation, 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:48-49 (helper)

  Helper function to format the API response into MCP content format, used by list_delegates.
  const formatResponse = (response: any) => ({ content: [{ type: "text", text: JSON.stringify(response) }] })