Codex CLI · AI coding agents

Codex CLI is OpenAI’s open-source coding agent for the terminal. It runs an interactive terminal UI (TUI) against your local repository, edits files and runs shell commands inside an OS-enforced sandbox, and can also run non-interactively in scripts and CI. A separate Codex cloud product runs tasks in OpenAI-managed containers; this section covers the local CLI.

Repository: github.com/openai/codex
Official docs: developers.openai.com/codex

Install

# macOS / Linux (install script)
curl -fsSL https://chatgpt.com/codex/install.sh | sh

# npm
npm install -g @openai/codex

# Homebrew
brew install --cask codex

On Windows, use the PowerShell installer:

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

Prebuilt binaries are also published on GitHub Releases. Re-running the same install command updates Codex; codex update self-updates when the installed release supports it.

First run and authentication

codex          # launch the interactive TUI
codex login    # sign in (browser-based ChatGPT OAuth by default)

You can sign in with a ChatGPT account (Plus/Pro/Business/Edu/Enterprise plans) or with an API key:

printenv OPENAI_API_KEY | codex login --with-api-key   # API key via stdin
codex login --device-auth                              # device-code flow
codex login status                                     # check auth state (exits 0 when logged in)

Credentials are cached at ~/.codex/auth.json or in the OS credential store. For automation, the CODEX_API_KEY environment variable provides single-run API-key auth. See Codex CLI terminal commands for the full command reference.

Quick start

# Interactive session with the recommended local combo
codex --sandbox workspace-write --ask-for-approval on-request

# One-shot non-interactive run (great for scripts)
codex exec "Summarize what this repo does"

# Resume your most recent session in this directory
codex resume --last

Inside the TUI, type / to open the slash-command popup and @ to attach files. Try /init to generate an AGENTS.md scaffold for your project, then ask Codex to explain the codebase.

In this section

File	What it covers
Codex CLI slash commands	Every verified `/command` in the TUI, plus deep-dives on the most important ones
Codex CLI terminal commands	Terminal commands: `codex`, `exec`, `resume`, `login`, `mcp`, `review`, `apply`, `cloud`, and more
Codex CLI flags	Global and `codex exec` flags, grouped by purpose
Codex CLI configuration	`config.toml`: location, key fields, profiles, precedence, project trust
Codex CLI project instructions (AGENTS.md)	`AGENTS.md` discovery, overrides, size limits, and an example
Codex CLI subagents	Subagents: built-ins, custom agent TOML files, spawn/wait tools
Codex CLI skills	Skills (`SKILL.md`): structure, discovery, invocation, plugins
Codex CLI and MCP servers	Connecting MCP servers with `codex mcp add` and `config.toml`
Codex CLI permissions, sandbox, and approvals	Approval policies, sandbox modes, platform notes, safety warnings
Codex CLI workflows	Mini-workflows: understand, build, debug, refactor, review

Last verified: 2026-09-07

Official sources:

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