OptionalbuffersOptional binary buffers attached to message
OptionalchannelCommunication channel (e.g., 'shell', 'iopub')
Message content payload
Message header containing protocol metadata
ISO timestamp when message was created
Unique message identifier
Message type (e.g., 'execute_request', 'execute_reply')
Session identifier
Username of the sender
Jupyter message protocol version
Message metadata object
Header of the parent message this message responds to
Jupyter message structure according to the protocol.