OpenAI Codex

OpenAI Codex is an agentic software-development tool that can inspect repositories, edit files, run commands and tests, review code, and carry multi-step engineering tasks through to a working result.

Developers can use it interactively from the command line, IDE integrations, and desktop experience, or delegate work to isolated cloud environments. Codex supports repository instructions and reusable skills, can work on multiple tasks in parallel, and is included with eligible ChatGPT plans; limited access is currently also available on the free tier.