OpenAI Codex CLI Freemium

Codex CLI is OpenAI's open-source terminal coding agent, now powered by GPT-5

Coding
Visit Website

OpenAI Codex CLI is a free, open-source coding agent that runs in your terminal. Install it with npm i -g @openai/codex, authenticate with ChatGPT or an API key, and it reads your repository, writes patches and executes shell commands on request.

What is OpenAI Codex CLI?

Codex CLI is a Rust-based command-line agent published by OpenAI under the Apache-2.0 licence. It’s the terminal counterpart to the Codex IDE extensions and the cloud Codex agent. You point it at a working directory, describe a change, and it proposes diffs that you approve or reject before anything touches disk.

The original 2025 release defaulted to o4-mini; current versions let you select GPT-5 and GPT-5-Codex tiers, which are tuned for longer agentic runs.

Codex CLI Features

  • Three approval modes — Suggest (read-only), Auto Edit (write files, ask before commands) and Full Auto (run everything in a sandbox).
  • Repo-aware context — indexes the project so it understands imports and conventions.
  • Multimodal input — attach screenshots or design mockups to a prompt.
  • Sandboxing — macOS Seatbelt and Linux Landlock/seccomp restrict network and filesystem access in Full Auto.
  • Local config via ~/.codex/config.toml — set default model, approval mode and per-project overrides.
  • Open source — Apache-2.0, so you can read exactly what it does before trusting it with a repo.

    • How Much Does Codex CLI Cost?

    The tool is free. What you pay for is model access. Signing in with a ChatGPT Plus ($20/month) or Pro ($200/month) account includes Codex usage with periodic rate limits. Alternatively, paste an OpenAI API key and pay per token — GPT-5 at $1.25 per million input and $10 per million output. Codex also accepts compatible third-party providers, so you can point it at a cheaper endpoint if you want.

    What Is Codex CLI Good At?

  • Scripted refactors — renaming an API across a repo, then running the test suite to confirm.
  • Legacy code archaeology — “explain what this module does and list its external calls”.
  • Test generation — writing pytest or Jest coverage for untested functions.
  • CI-friendly automation — headless runs in a container for routine maintenance.
  • Terminal-native developers — you never leave tmux for a new IDE.

    • Who Should Use Codex CLI and Who Should Not

    If you’re comfortable in a shell and want an agent without switching editors, this is one of the cleaner options available. The approval flow is sensible, and the sandbox on Full Auto is a real safeguard rather than a marketing line.

    If you want inline completions, tab-to-accept ghost text and a graphical diff view, a VS Code extension or Cursor will feel more natural. Codex CLI is deliberately terse. And Full Auto still deserves caution on repos containing credentials — the sandbox helps, but the agent will happily rewrite files it misjudges.

    Quick Summary

  • OpenAI Codex CLI is a free, Apache-2.0 licensed terminal coding agent.
  • Install with npm i -g @openai/codex; sign in with ChatGPT or an API key.
  • Supports GPT-5 and GPT-5-Codex models, plus third-party OpenAI-compatible endpoints.
  • Three approval modes range from read-only suggestions to sandboxed full autonomy.
  • Usage is included with ChatGPT Plus at $20/month, or billed per token via API.

    • Related Tools

    Retool

    Retool Freemium

    Low-code platform to build internal tools and AI apps fast
    Cursor CLI

    Cursor CLI Paid

    Cursor's terminal agent that brings its Composer model to your shell and CI
    Crush

    Crush Freemium

    Charm's terminal-first AI coding agent with a slick TUI and multi-model support
    Ellipsis

    Ellipsis Paid

    An AI reviewer that reads every pull request like a senior engineer
    Emergent

    Emergent Freemium

    Describe an app in a sentence, get a working full-stack build
    Traycer

    Traycer Freemium

    Plan-first AI coding that shows the spec before it writes code

    Related Tutorials