Codex CLI
OpenAI's open-source Rust coding agent that edits repos and runs code in a sandboxed terminal session.
About
Codex CLI is OpenAI's terminal-native coding agent: a Rust binary that reads your repository, proposes and applies edits, and executes commands inside a sandbox, with configurable approval modes ranging from suggest-only to full auto. The Rust implementation (the codex-rs workspace) keeps startup fast and drops the Node runtime dependency of early releases, though npm remains an install path alongside Homebrew, direct binary downloads from GitHub Releases, and shell installers for macOS, Linux, and Windows. Authentication works by signing in with a ChatGPT Plus, Pro, Business, Edu, or Enterprise account, or by supplying an OpenAI API key with extra setup, and the same agent surfaces through IDE extensions for VS Code, Cursor, and Windsurf plus a hosted version at chatgpt.com/codex. The code is fully open under Apache-2.0, with about 102,000 GitHub stars and an active contributor community that OpenAI supports through an open-source fund. Documentation, build guides, and configuration references live at developers.openai.com/codex.
Should you use Codex CLI?
Pick it when
Pick Codex CLI when you already have a ChatGPT Plus, Pro, Business, or Enterprise plan and want an open source terminal agent that runs commands inside a sandbox, with approval levels from suggest-only to full auto.
Look elsewhere when
Skip it if your team does not pay OpenAI, since sign-in assumes a ChatGPT plan or an OpenAI API key. OpenCode and Crush treat many providers, including local models, as first-class, and Claude Code suits Anthropic shops.
Alternatives to Codex CLI
- Claude Code
Similar terminal agent with hooks, subagents, plugins, and @claude on GitHub, but proprietary and on a paid Anthropic plan, where Codex CLI's code is Apache-2.0.
- OpenCode
MIT and provider-agnostic so you can swap models per task, where Codex CLI is built around OpenAI accounts and adds a hosted chatgpt.com version.
- Gemini CLI
Same open Apache-2.0 terminal agent pattern for Gemini, with Search grounding and checkpointing, but it now needs a paid API key or Code Assist license.
- Crush
Go TUI that switches providers mid-session with LSP context and very broad OS support, but its FSL license is source-available rather than Apache-2.0.
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Details
- Category
- AI Code Assistants
- Price
- Free
- Platform
- Local/Desktop
- Difficulty
- Easy (2/5)
- License
- Apache-2.0
- Added
- Jul 29, 2026