A chatbot answers the last message. An agent carries a task. That difference sounds small until the work spans research, verification, drafting, revision, and delivery. At that point the user becomes the coordinator in a chat product. Rush moves that coordination into the runtime.
The interface still begins with language because language is the cleanest way to express intent. But the result should not be another transcript to clean up later. It should be a report, a draft, a comparison, a plan, or a handoff that can survive the session that created it.
This is why Rush is organized around agents and artifacts. The conversation starts the work. It is not the work.