Fastmail MCP Server

Instructions

Implementation Reference

• src/jmap-client.ts:426-443 (handler)

  Core handler function that executes the tool logic by making a JMAP Email/get request to retrieve attachments for the specified email ID.
  async getEmailAttachments(emailId: string): Promise<any[]> { const session = await this.getSession(); const request: JmapRequest = { using: ['urn:ietf:params:jmap:core', 'urn:ietf:params:jmap:mail'], methodCalls: [ ['Email/get', { accountId: session.accountId, ids: [emailId], properties: ['attachments'] }, 'getAttachments'] ] }; const response = await this.makeRequest(request); const email = response.methodResponses[0][1].list[0]; return email?.attachments || []; }
• src/index.ts:453-464 (schema)

  Defines the input schema and metadata for the MCP tool, specifying that it requires an 'emailId' string parameter.
  name: 'get_email_attachments', description: 'Get list of attachments for an email', inputSchema: { type: 'object', properties: { emailId: { type: 'string', description: 'ID of the email', }, }, required: ['emailId'], },
• src/index.ts:970-985 (registration)

  MCP server request handler case that dispatches the tool call, validates input, invokes the JmapClient handler, and formats the response.
  case 'get_email_attachments': { const { emailId } = args as any; if (!emailId) { throw new McpError(ErrorCode.InvalidParams, 'emailId is required'); } const client = initializeClient(); const attachments = await client.getEmailAttachments(emailId); return { content: [ { type: 'text', text: JSON.stringify(attachments, null, 2), }, ], }; }
• src/index.ts:452-465 (registration)

  Tool registration entry in the MCP server's tools list, including name, description, and schema.
  { name: 'get_email_attachments', description: 'Get list of attachments for an email', inputSchema: { type: 'object', properties: { emailId: { type: 'string', description: 'ID of the email', }, }, required: ['emailId'], }, },