get_attachment
Retrieve email attachments from Gmail messages by specifying the message and attachment IDs to access files sent in emails.
Instructions
Get a message attachment
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| messageId | Yes | ID of the message containing the attachment | |
| id | Yes | The ID of the attachment |
Implementation Reference
- src/index.ts:702-714 (registration)Registration of the 'get_attachment' MCP tool, including input schema (messageId and id), description, and handler function that calls the Gmail API to fetch the attachment.server.tool("get_attachment", "Get a message attachment", { messageId: z.string().describe("ID of the message containing the attachment"), id: z.string().describe("The ID of the attachment"), }, async (params) => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.messages.attachments.get({ userId: 'me', messageId: params.messageId, id: params.id }) return formatResponse(data) }) } )
- src/index.ts:708-713 (handler)The handler function executes the tool logic: authenticates via handleTool, calls gmail.users.messages.attachments.get with userId 'me', messageId and id from params, formats response.async (params) => { return handleTool(config, async (gmail: gmail_v1.Gmail) => { const { data } = await gmail.users.messages.attachments.get({ userId: 'me', messageId: params.messageId, id: params.id }) return formatResponse(data) }) }
- src/index.ts:705-707 (schema)Zod input schema defining required string parameters: messageId (ID of the message containing the attachment) and id (ID of the attachment).messageId: z.string().describe("ID of the message containing the attachment"), id: z.string().describe("The ID of the attachment"), },
- src/index.ts:50-80 (helper)Shared handleTool helper used by get_attachment (and other tools) to manage OAuth2 authentication, credential validation, Gmail client creation, and error handling specific to auth issues.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)Helper function to format tool responses as MCP content array with JSON stringified text.const formatResponse = (response: any) => ({ content: [{ type: "text", text: JSON.stringify(response) }] })