Codex CLI — CodexHow

Guides to the Codex CLI itself — installing and updating it, the slash commands and subcommands it actually ships with, writing a project's AGENTS.md, resuming a previous session, and the config file that controls almost everything else about how it behaves. These are written against the CLI's own published reference, not a general impression of how a coding agent "usually" works.

If you're new to the CLI, start with installation and the slash commands, then read the config file reference before you touch sandbox or approval flags in earnest — the config file is where most per-project defaults actually live, and understanding it first makes the sandbox guides make more sense.