X‑API‑Key header issued from the ARC‑AGI‑3 web console.
Important: Session Affinity via CookiesGames are stateful and require session affinity. The server sets cookies (especially
AWSALB* cookies) in responses that must be included in all subsequent requests for the same game session. These cookies route requests to the correct backend instance maintaining your game state. Most HTTP clients handle cookies automatically, but ensure your client preserves and sends cookies received from RESET and ACTION responses.
