OpenAI Codex CLI: The Open-Source Coding Agent That Runs in Your Terminal

A Coding Agent That Lives in Your Terminal

Codex CLI, the command-line version of OpenAI's open-source coding agent Codex — first released in April 2025 — has recently returned to GitHub's trending list. The repository describes it simply as "a lightweight coding agent that runs in your terminal."

Codex CLI runs directly in a developer's terminal, working with local files and commands. To use it, you need to sign in with a ChatGPT account or set up an API key. OpenAI actually maintains several versions under the Codex name — a code editor extension, a desktop app, and a cloud-based version accessible through a browser — alongside the CLI.

Four Ways to Install

The repository's documentation lays out installation commands for each operating system. On Mac and Linux, you can use the following curl script:

curl -fsSL https://chatgpt.com/codex/install.sh | sh

On Windows, you'd use this PowerShell command:

powershell -ExecutionPolicy ByPass -c "irm https://chatgpt.com/codex/install.ps1 | iex"

By default, this installer script pulls files from releases.openai.com/codex, but it automatically falls back to GitHub Releases if something goes wrong. Setting the environment variable CODEX_INSTALLER_USE_RELEASES_OPENAI_COM to false forces it to use GitHub Releases from the start instead.

The repository's official README also lists npm and Homebrew installation commands.

npm install -g @openai/codex

brew install --cask codex

If you'd rather download the executable directly, the GitHub Releases page offers builds for Apple Silicon (codex-aarch64-apple-darwin.tar.gz) and Intel Macs (codex-x86_64-apple-darwin.tar.gz), along with x86_64 and arm64 archives for Linux. Once unzipped, each archive contains a single executable with the platform name attached — the repository recommends renaming it to codex for convenience.

Getting Started

1. Once you've installed it using one of the four methods above, the codex command becomes available in your terminal.
2. Typing codex in your terminal launches it and brings up a screen asking you to choose a sign-in method.
3. Selecting "Sign in with ChatGPT" lets you log in with your account. OpenAI supports both this option and API key authentication.
4. If you don't have a ChatGPT subscription, you can connect an API key instead — though the repository notes this requires some additional setup.
5. Once you're signed in, you can start giving it natural-language requests right away — asking it to fix code or create new files.

What Sets CLI, IDE, App, and Web Apart

Even under the same Codex brand, where each version runs and how you access it varies quite a bit.

Version	Where It Runs	How to Access
Codex CLI	Local terminal	Install via curl, npm, or brew
Codex IDE	Inside VS Code, Cursor, or Windsurf	IDE installation page
Codex App	Desktop	codex app command or app landing page
Codex Web	Browser (cloud)	chatgpt.com/codex

If you want to use it right inside your code editor, just install the extension from the IDE page. If you'd rather have it in its own window instead of a terminal, grab the desktop app. And if you want to hand off work entirely through a browser without any local setup, Codex web is the cloud-based option — the key difference from CLI being that the work runs on OpenAI's servers instead of your own machine's resources.

Same Name, Different Ways to Run It

OpenAI's official documentation treats Codex CLI, the IDE extension, the desktop app, and Codex web as distinct access methods. This article specifically covers the terminal-based Codex CLI — user numbers from other Codex products or enterprise services shouldn't be conflated with CLI usage statistics.

You can find the full source code and installation files for Codex CLI at the github.com/openai/codex repository.

Editor's Note

Codex CLI's main strength is that it works directly with files and commands in your terminal. That said, running locally doesn't necessarily tell you the full scope of how data gets processed — don't assume otherwise based on that description alone.

Before adopting it for real work, it's worth figuring out first which access method — CLI, IDE, app, or web — actually fits your team's workflow.

Since the official documentation treats CLI, IDE, app, and web as separate paths, teams should pick whichever matches where the work happens. CLI suits terminal-centric development, the IDE extension fits work done inside an editor, and Codex web works best for browser-based delegation.

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Correction (2026-08-24) — The original article implied that Codex CLI had just been open-sourced. In fact, the repository was created on April 13, 2025. The lead and summary have been corrected accordingly.