Codex CLI vs Codex cloud: where does my code actually run?

What I'm trying to do

I'm confused about Codex. There's a CLI I install on my machine, and there's also Codex in the cloud that works on my GitHub repo.

Where does my code actually run in each case? What can each one touch, and when should I use which?

From the Codex docs, checked on 2026-10-04:

• Codex CLI works against your local repository. It inspects files, makes edits and runs the tools already installed on your machine.


• Codex Cloud gives each task its own workspace on the repositories you choose. Network access and credentials are set in the environment settings.


• Codex reads AGENTS.md files before it does any work.