OpenAI's Dev Day 2024 demo ran on an o1 preview model that could not run or check its own code, so Romain Huet had to cross his fingers live on stage. A year later, the same kind of demo ran a full camera and lighting rig, because the model could now test its own work. Alexander Embiricos and Huet use that jump to show how fast Codex is moving: new model releases went from every 15 months to about every 6 weeks. They walk through why Codex is built on the same responses API, open source harness, and AGENTS ...