Microsoft MCP

Instructions

Implementation Reference

• src/microsoft_mcp/tools.py:812-837 (handler)

  The core handler function for the 'get_attachment' tool. It retrieves the attachment from Microsoft Graph API using the provided email_id and attachment_id, decodes the base64-encoded contentBytes, saves the file to the specified save_path, and returns metadata including name, content_type, size, and saved path.

  def get_attachment(
      email_id: str, attachment_id: str, save_path: str, account_id: str
  ) -> dict[str, Any]:
      """Download email attachment to a specified file path"""
      result = graph.request(
          "GET", f"/me/messages/{email_id}/attachments/{attachment_id}", account_id
      )
  
      if not result:
          raise ValueError("Attachment not found")
  
      if "contentBytes" not in result:
          raise ValueError("Attachment content not available")
  
      # Save attachment to file
      path = pl.Path(save_path).expanduser().resolve()
      path.parent.mkdir(parents=True, exist_ok=True)
      content_bytes = base64.b64decode(result["contentBytes"])
      path.write_bytes(content_bytes)
  
      return {
          "name": result.get("name", "unknown"),
          "content_type": result.get("contentType", "application/octet-stream"),
          "size": result.get("size", 0),
          "saved_to": str(path),
      }

• src/microsoft_mcp/server.py:3-14 (registration)

  The server entry point imports the FastMCP instance (mcp) from tools.py where all tools including get_attachment are decorated and registered, and calls mcp.run() to start the MCP server, making the tool available.

  from .tools import mcp
  
  
  def main() -> None:
      if not os.getenv("MICROSOFT_MCP_CLIENT_ID"):
          print(
              "Error: MICROSOFT_MCP_CLIENT_ID environment variable is required",
              file=sys.stderr,
          )
          sys.exit(1)
  
      mcp.run()

• src/microsoft_mcp/tools.py:5-8 (registration)

  Creates the FastMCP server instance named 'microsoft-mcp' to which all tools, including get_attachment, are registered via @mcp.tool decorators.

  from fastmcp import FastMCP
  from . import graph, auth
  
  mcp = FastMCP("microsoft-mcp")