Gmail MCP Server

Instructions

Implementation Reference

• src/index.ts:1261-1274 (handler)

  The handler function for the 'insert_smime_info' tool, registered via server.tool(). It calls the Gmail API to insert S/MIME info for a send-as alias using handleTool wrapper. Includes inline schema definition.
  server.tool("insert_smime_info", "Insert (upload) the given S/MIME config for the specified send-as alias", { sendAsEmail: z.string().describe("The email address that appears in the 'From:' header"), encryptedKeyPassword: z.string().describe("Encrypted key password"), pkcs12: z.string().describe("PKCS#12 format containing a single private/public key pair and certificate chain") }, async (params) => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.settings.sendAs.smimeInfo.insert({ userId: 'me', sendAsEmail: params.sendAsEmail, requestBody: params }) return formatResponse(data) }) } )
• src/index.ts:1264-1267 (schema)

  Input schema (Zod) for the 'insert_smime_info' tool, defining parameters sendAsEmail, encryptedKeyPassword, and pkcs12.
  sendAsEmail: z.string().describe("The email address that appears in the 'From:' header"), encryptedKeyPassword: z.string().describe("Encrypted key password"), pkcs12: z.string().describe("PKCS#12 format containing a single private/public key pair and certificate chain") },
• src/index.ts:1261-1274 (registration)

  Registration of the 'insert_smime_info' tool using server.tool(), including description, schema, and handler.
  server.tool("insert_smime_info", "Insert (upload) the given S/MIME config for the specified send-as alias", { sendAsEmail: z.string().describe("The email address that appears in the 'From:' header"), encryptedKeyPassword: z.string().describe("Encrypted key password"), pkcs12: z.string().describe("PKCS#12 format containing a single private/public key pair and certificate chain") }, async (params) => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.settings.sendAs.smimeInfo.insert({ userId: 'me', sendAsEmail: params.sendAsEmail, requestBody: params }) return formatResponse(data) }) } )
• src/index.ts:50-80 (helper)

  Shared helper function 'handleTool' used by 'insert_smime_info' and other tools for authentication, Gmail client creation, and error handling.
  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) { // Check for specific authentication errors if ( error.message?.includes("invalid_grant") || error.message?.includes("refresh_token") || error.message?.includes("invalid_client") || error.message?.includes("unauthorized_client") || error.code === 401 || error.code === 403 ) { return formatResponse({ error: `Authentication failed: ${error.message}. Please re-authenticate by running: npx @shinzolabs/gmail-mcp auth`, }); } return formatResponse({ error: `Tool execution failed: ${error.message}` }); } }