What it is
OpenAI's open-source coding agent that runs locally on your computer. The README recommends signing in with a ChatGPT account so Codex is used as part of your plan; an API key works with extra setup.
Install
macOS, Linux
$ curl -fsSL https://chatgpt.com/codex/install.sh | sh
Windows
$ powershell -ExecutionPolicy ByPass -c "irm https://chatgpt.com/codex/install.ps1 | iex"
npm
$ npm install -g @openai/codex
Homebrew
$ brew install --cask codex
Start
$ codex
Choose "Sign in with ChatGPT".
Commands are copied from the source on the checked date. Installers change; if one fails, the source link has the current version.
Walk through it step by step in LearnTry it in the playground