What does the VARTA error `session_already_ended` mean?

HTTP status: 409  ·  Type: invalid_request_error

What it means

The session is closed and can't accept another turn.

What causes it

Raised by POST /v1/sessions/{session_id}/turn when the session's ended_at is already set (backend/app/api/v1/sessions.py).

What to do

Open a new session with POST /v1/agents/{agent_id}/load rather than reusing one that has ended.