agent engine playground session with a specific user_id?

[markns]

how can I create a agent engine playground session with a specific user_id?

Gemini Cloud Assist tells me I should create a session via the api:

session = await remote_agent_engine.async_create_session(user_id="....")

But when I do that the session is marked as read only in the playground

Any session created in the playground just seems to default to user_id vais-query-reasoning-engine