Notably, GPT-5.3-Codex is the first OpenAI model that was used to create itself: The team used early versions of the model to debug its training, manage its deployment, and diagnose test results and ...
Dan tested Codex 5.3 on Proof, a macOS markdown editor that he's been vibe coding that tracks the origin of every piece of text—whether it was written by a human or generated by AI—and lets users ...