get_message

Instructions

Implementation Reference

• src/index.ts:548-557 (handler)

  Inline handler function for the 'get_message' MCP tool. It invokes the shared handleTool utility with an API callback that fetches the full Gmail message by ID, processes its payload (decoding bodies, filtering headers), and returns a formatted text/JSON response.

  async (params) => {
    return handleTool(config, async (gmail: gmail_v1.Gmail) => {
      const { data } = await gmail.users.messages.get({ userId: 'me', id: params.id, format: 'full' })
  
      if (data.payload) {
        data.payload = processMessagePart(data.payload, params.includeBodyHtml)
      }
  
      return formatResponse(data)
    })

• src/index.ts:544-547 (schema)

  Input schema for 'get_message' tool using Zod: requires 'id' string (message ID), optional 'includeBodyHtml' boolean to control HTML body inclusion in response.

  {
    id: z.string().describe("The ID of the message to retrieve"),
    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:542-559 (registration)

  Registration of the 'get_message' tool on the McpServer instance, specifying name, description, input schema, and handler function.

  server.tool("get_message",
    "Get a specific message by ID with format options",
    {
      id: z.string().describe("The ID of the message to retrieve"),
      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) => {
        const { data } = await gmail.users.messages.get({ userId: 'me', id: params.id, format: 'full' })
  
        if (data.payload) {
          data.payload = processMessagePart(data.payload, params.includeBodyHtml)
        }
  
        return formatResponse(data)
      })
    }
  )

• src/index.ts:49-65 (helper)

  Core helper function used by 'get_message' (and all tools): handles OAuth2 client creation/validation, Gmail client setup, executes the provided Gmail API callback, catches errors.

  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)

  Recursive helper to process Gmail message parts for 'get_message': decodes base64 bodies for text/* (html if flagged), recurses into parts, retains only key headers (Date, From, To, Subject, etc.).

  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
  }