OpenAI launches GPT-5.3-Codex, which it says runs 25% faster, enabling longer-running tasks, and "is our first model that was instrumental in creating itself" (David Gewirtz/ZDNET)

David Gewirtz / ZDNET: OpenAI launches GPT-5.3-Codex, which it says runs 25% faster, enabling longer-running tasks, and“is our first model that was instrumental in creating itself”  —  ZDNET's key takeaways  — GPT-5.3-Codex helped debug and deploy parts of itself.  — Codex can be steered mid-task without losing context.