Overview
- GPT-5.3-Codex is available now to paid ChatGPT users across the Codex app, CLI, IDE extensions and the web, with broader API access planned.
- OpenAI says early versions of the model helped debug training runs, manage deployment and assess evaluations, accelerating its own development.
- The company reports roughly 25% faster throughput versus GPT-5.2-Codex and leading internal results on SWE‑Bench Pro, Terminal‑Bench 2.0 and OSWorld‑Verified.
- The release targets end‑to‑end workflows: the model can be steered mid‑task, run for extended periods and support work beyond coding such as docs, research and presentations.
- Citing elevated cyber risk, OpenAI classifies the model as high capability for cybersecurity, is restricting advanced uses, and is offering $10 million in API credits to support defensive research as competition with Anthropic intensifies.