unknown_user

MCP as.userId does not name an existing user.

Common causes

• A wrong id. Unknown users are an error, never an anonymous fallback.

How to fix

Use an existing user id, or "anonymous".

Response

{
  "type": "https://castra.mehmetozer.dev/problems/unknown_user",
  "title": "…",
  "status": 400,
  "detail": "…"
}

detail says what exactly went wrong for this request.