s3-mcp

Instructions

Implementation Reference

• src/s3_mcp.py:395-414 (handler)

  The handler function for the 'download_file' tool, registered via @mcp.tool() decorator. It invokes the helper logic and formats the success response.

  @mcp.tool()
  def download_file(
      bucket: str,
      key: str,
      filename: str,
  ) -> str:
      """Downloads an object from an S3 bucket to a file.
  
      Args:
          bucket (str): The name of the bucket to download from.
          key (str): The name of the key to download from.
          filename (str): The path to the file to download to.
  
      Returns:
          str: JSON formatted success message.
      """
      _download_file_logic(bucket=bucket, key=key, filename=filename)
      return format_response(
          {"status": "success", "message": f"File '{key}' from bucket '{bucket}' downloaded to '{filename}'."}
      )

• src/s3_mcp.py:375-393 (helper)

  The supporting helper function containing the core download logic using boto3 S3 client's download_file method.

  def _download_file_logic(
      bucket: str,
      key: str,
      filename: str,
  ) -> None:
      """Core logic to download an object from an S3 bucket.
  
      Args:
          bucket (str): The S3 bucket name.
          key (str): The S3 object key.
          filename (str): The local path to download the file to.
      """
      client = get_s3_client()
      client.download_file(
          Bucket=bucket,
          Key=key,
          Filename=filename,
      )

• src/s3_mcp.py:396-400 (schema)

  Input schema defined by function parameters with type annotations: bucket (str), key (str), filename (str); returns str.

  def download_file(
      bucket: str,
      key: str,
      filename: str,
  ) -> str: