OpenAI opened an Agents API in public beta on September 10, 2026, selling Codex’s backend as a service to run agents unattended for days. The same day, the company paused sign-ups for its Pro plan under GPT-6 Astra demand: the bottleneck is shifting from models to infrastructure.

On September 3, 2026, OpenAI unveiled GPT-6 Astra, the first model it classifies as ‘critical’ for cybersecurity under its Preparedness Framework, then released a public version the next day that refuses offensive requests. For defenders, the full capabilities sit behind the Daybreak Blue program, not the public API.