Open-source coding agents
OpenAI Codex CLI on GitHub: what it does and how to use it with AI agents
OpenAI's open-source coding agent that runs in your terminal.
Stars, license and last push from the GitHub API, checked 2026-10-26
| Repo | openai/codex |
|---|---|
| Stars | 131,000+ |
| License | Apache-2.0 |
| Last push | 2026-10-26 |
| Language | Rust |
What OpenAI Codex CLI does
Codex reads your repo, edits files and runs commands from the terminal. It follows instructions in an AGENTS.md file, supports MCP servers and has approval modes that control what it can run without asking.
Who it is for
Developers with a ChatGPT plan or an OpenAI API key who want a terminal agent they can inspect.
How to use OpenAI Codex CLI with Claude Code, Codex or Cursor
Install: npm i -g @openai/codexRun codex in your project and sign in with ChatGPT or an API key.Add an AGENTS.md with your build and test commands.Start in a mode that asks before running commands.
Tip: The same AGENTS.md file can guide Cursor and other agents too, so write it once.
The loadout for this repo
See the full tool stack, prompts and costs in Best AI coding agent setup.
Related repos
- Gemini CLI: Google's open-source agent that brings Gemini into your terminal.
- Anthropic Agent Skills: Public repo of Agent Skills: folders of instructions and scripts an agent loads when needed.
OpenAI Codex CLI FAQ
Is Codex CLI open source?
Yes, under Apache-2.0. Model usage is billed through your ChatGPT plan or API key.
Does Codex support MCP?
Yes. MCP servers go in ~/.codex/config.toml.
Codex vs Claude Code?
See our Cursor vs Claude Code vs Codex comparison for pricing and limits.
Star counts change daily. Always read a repo's license and code before running it. All repos