Codex CLI

Codex CLI is OpenAI's current terminal agent, not the 2021 Codex model page this entry used to point at. Official docs say it inspects your local repository, edits files, runs the tools already on the machine, and can run non-interactively as codex exec in scripts and CI. It sits next to the IDE extension, Codex cloud, and ChatGPT desktop. Usage is shared with ChatGPT Work and is included in ChatGPT Free, Go, Plus, Pro, Business, Edu, or Enterprise.

Key Features

• Local repo loop: Explore, plan, edit, and run project tools in one terminal session. You pick model, reasoning effort, permissions, and allowed commands.
• Install paths: curl -fsSL https://chatgpt.com/codex/install.sh | sh on macOS/Linux, a PowerShell installer on Windows, npm i -g @openai/codex, or brew install --cask codex.
• Skills, plugins, MCP, AGENTS.md: Package repeatable instructions, connect team tools, and keep project rules in the repo.
• Review without writing: Dedicated review against uncommitted changes, a commit, or a base branch. Codex reports findings and does not modify the tree.
• Automation: codex exec for CI, GitHub Action, sandboxing, and optional cloud isolation.

Use Cases

• Daily terminal work when you already live in git and a shell.
• CI review that should not touch the working tree.
• ChatGPT-plan shops that want the same GPT-5.6 family in CLI, IDE, and cloud.

Pricing

Official Codex pricing (accessed 2026-08-17) is the ChatGPT plan stack. Individual cards include Free at $0, Go at $8/month, Plus at $20/month, and Pro from $100/month. Plus lists Codex on the web, CLI, IDE extension, and iOS, plus the GPT-5.6 family (Sol, Terra, Luna) and credit top-ups. ChatGPT Work usage and Codex share the same credits and limits. Recheck learn.chatgpt.com/docs/pricing before you publish a comparison.

Getting Started

1. Install with the official script, npm, or Homebrew.
2. cd into a repo, run codex, and sign in with ChatGPT (or another documented auth method).
3. Ask it to explain the project, then make one focused change. Create git checkpoints before and after.
4. Add AGENTS.md and only then wire codex exec into CI.

Frequently Asked Questions

Is this the 2021 OpenAI Codex model?

No. The old model docs URL is stale. This product is the 2026 ChatGPT Codex CLI.

Does Free include Codex?

Yes, at a "quick coding tasks" level. Serious weekly use is what Plus ($20) is sold for.

How is it different from Claude Code?

Claude Code is Anthropic's multi-surface agent. Codex CLI is OpenAI's, billed on ChatGPT plans, with codex exec and GPT-5.6.

Alternatives

• Claude Code: Anthropic's CLI/IDE/desktop/web agent.
• ChatGPT Plus: The chat plan that Plus-tier Codex rides on.
• Cursor: If you want the agent inside an editor, not a terminal.

Tips

1. Use codex resume to reopen a repo chat instead of starting from zero.
2. Pass --image when the bug is a screenshot.
3. Keep sandbox approvals tight in CI. Official security docs exist for a reason.

Conclusion

Codex CLI is the OpenAI terminal agent to standardize on if your team already pays for ChatGPT. Install from the CLI docs, sign in, and treat codex exec plus AGENTS.md as the production path, not a demo.