(user, agent) Parts (text, file, or JSON) JSON-RPC Task ID Status HTTP(S) Artifact Parts (text, file, or JSON) JSON-RPC Option 2: Tasks for stateful interactions Artifact - A tangible output generated by an agent during a task (for example, a document, image, or structured data) Task Status: - Unspecified - Submitted - Working - Completed - Failed - Cancelled - Input required - Rejected - Auth Required