Gmail MCP

Instructions

Implementation Reference

• src/index.ts:300-336 (registration)

  Registration of the 'list_drafts' tool on the MCP server, including description, input schema, and inline handler function.
  server.tool("list_drafts", "List drafts in the user's mailbox", { maxResults: z.number().optional().describe("Maximum number of drafts to return. Accepts values between 1-500"), q: z.string().optional().describe("Only return drafts matching the specified query. Supports the same query format as the Gmail search box"), includeSpamTrash: z.boolean().optional().describe("Include drafts from SPAM and TRASH in the results"), includeBodyHtml: z.boolean().optional().describe("Whether to include the parsed HTML in the return for each body, excluded by default because they can be excessively large"), }, async (params) => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { let drafts: Draft[] = [] const { data } = await gmail.users.drafts.list({ userId: 'me', ...params }) drafts.push(...data.drafts || []) while (data.nextPageToken) { const { data: nextData } = await gmail.users.drafts.list({ userId: 'me', ...params, pageToken: data.nextPageToken }) drafts.push(...nextData.drafts || []) } if (drafts) { drafts = drafts.map(draft => { if (draft.message?.payload) { draft.message.payload = processMessagePart( draft.message.payload, params.includeBodyHtml ) } return draft }) } return formatResponse(drafts) }) } )
• src/index.ts:308-335 (handler)

  The core handler function that performs the tool logic: calls Gmail API to list drafts with pagination, processes payloads using processMessagePart, and formats the response.
  async (params) => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { let drafts: Draft[] = [] const { data } = await gmail.users.drafts.list({ userId: 'me', ...params }) drafts.push(...data.drafts || []) while (data.nextPageToken) { const { data: nextData } = await gmail.users.drafts.list({ userId: 'me', ...params, pageToken: data.nextPageToken }) drafts.push(...nextData.drafts || []) } if (drafts) { drafts = drafts.map(draft => { if (draft.message?.payload) { draft.message.payload = processMessagePart( draft.message.payload, params.includeBodyHtml ) } return draft }) } return formatResponse(drafts) }) }
• src/index.ts:303-307 (schema)

  Zod schema defining the input parameters for the list_drafts tool.
  maxResults: z.number().optional().describe("Maximum number of drafts to return. Accepts values between 1-500"), q: z.string().optional().describe("Only return drafts matching the specified query. Supports the same query format as the Gmail search box"), includeSpamTrash: z.boolean().optional().describe("Include drafts from SPAM and TRASH in the results"), includeBodyHtml: z.boolean().optional().describe("Whether to include the parsed HTML in the return for each body, excluded by default because they can be excessively large"), },
• src/index.ts:49-65 (helper)

  Shared helper function used by list_drafts (and other tools) to handle OAuth2 authentication, credential validation, 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) { return `Tool execution failed: ${error.message}` } }
• src/index.ts:79-93 (helper)

  Helper function to process message parts: decodes bodies (unless HTML and not requested), recursively processes parts, and filters headers.
  const processMessagePart = (messagePart: MessagePart, includeBodyHtml = false): MessagePart => { if ((messagePart.mimeType !== 'text/html' || includeBodyHtml) && messagePart.body) { messagePart.body = decodedBody(messagePart.body) } if (messagePart.parts) { messagePart.parts = messagePart.parts.map(part => processMessagePart(part, includeBodyHtml)) } if (messagePart.headers) { messagePart.headers = messagePart.headers.filter(header => RESPONSE_HEADERS_LIST.includes(header.name || '')) } return messagePart }