Agents, Sessions, and messages

• An Agent stores model behavior, instructions, enabled capabilities, and optional linked resources.
• A Session groups a sequence of user and assistant messages for one Agent.
• A message is one user request, assistant response, clarification, or related execution content in that Session.

Opening an Agent or selecting New Session prepares an empty view; it does not create a persisted Session. The first non-empty submitted question creates it. A streamed assistant response can contain multiple blocks and still represent one answer message.

Deleting a Session is not the same as deleting its Agent. Access to a shared Agent also does not imply permission to send messages in every Session.