Codex (cloud agent) and codex-1
Codex, a cloud software-engineering agent powered by codex-1 (an o3 variant), runs many tasks in parallel in sandboxes and proposes pull requests.
codex-1 is o3 tuned with RL on real coding tasks to match human PR style and iterate on tests. Each task runs 1 to 30 minutes in its own sandbox preloaded with the repo and follows AGENTS.md files. Also released codex-mini-latest, an o4-mini variant for the CLI, at $1.50/$6 per million tokens.
- Date
- Friday, 16 May 2025
- Lab
- OpenAI
- Kind
- product
- Access
- research preview
- Price
- ChatGPT Pro, Business, Enterprise at launch; Plus from 2025-06-03
Figures
| Measure | Value | Measured by |
|---|---|---|
| codex-mini-latest API price (input / output per 1M tokens) | $1.50 / $6 75% prompt-caching discount | company |
Codex became OpenAI's umbrella brand for coding models and tools (GPT-5-Codex, the Codex app, Codex Security). Simon Willison noted on 2025-12-31 that docs now call the web app Codex web; OpenAI says cloud tasks run on a hosted runtime.
Sources
- openai.com/index/introducing-codex/
- simonwillison.net/2025/May/16/openai-codex/
- developers.openai.com/api/docs/changelog
This record was checked against its sources on 6 October 2026. How we check