What you will learn
- Install and verify Codex CLI.
- Choose between the CLI, IDE extension, app, and cloud tasks.
- Open a first session inside a repository.
Minimal setup
Codex CLI works with the files and tools on your machine. OpenAI recommends the standalone installer on macOS and Linux; npm remains a cross-platform alternative. Check the version before signing in.
# Recommended on macOS and Linux curl -fsSL https://chatgpt.com/codex/install.sh | sh # npm alternative npm install -g @openai/codex codex --version cd ~/code/my-project codex
On first launch, follow the sign-in flow shown by Codex. Inside a session, /status summarizes the active directory, model, and permissions.
/status /permissions /model
Choose a surface
- CLI for fast local work, scripts, Git, and terminal-native workflows.
- IDE for changes closely tied to the file or selection in view.
- App for longer tasks, visual review, and coordinating parallel work.
- Cloud for delegated work in a prepared, isolated environment.
First check
Start with a read-only request: “Summarize the architecture, tell me how tests run, and do not edit files.” Confirm that Codex identifies the language, package manager, and Git state correctly.