Gmail MCP Server

Instructions

Implementation Reference

• src/index.ts:455-466 (registration)

  Registration of the 'delete_label' tool, including schema (id parameter) and handler function that calls Gmail API to delete the label by ID.
  server.tool("delete_label", "Delete a label", { id: z.string().describe("The ID of the label to delete") }, async (params) => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.labels.delete({ userId: 'me', id: params.id }) return formatResponse(data) }) } )
• src/index.ts:460-466 (handler)

  Handler function for 'delete_label' tool: authenticates via handleTool and deletes the label using gmail.users.labels.delete.
  async (params) => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.labels.delete({ userId: 'me', id: params.id }) return formatResponse(data) }) } )
• src/index.ts:457-459 (schema)

  Input schema for 'delete_label' tool using Zod: requires 'id' string (label ID).
  { id: z.string().describe("The ID of the label to delete") },
• src/index.ts:50-80 (helper)

  Shared helper function 'handleTool' used by all tools, including 'delete_label', for OAuth2 authentication, Gmail client creation, API call execution, 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}` }); } }
• src/index.ts:48-48 (helper)

  Shared helper 'formatResponse' used to format tool responses as MCP content.
  const formatResponse = (response: any) => ({ content: [{ type: "text", text: JSON.stringify(response) }] })