Codex CLI Plan Mode: The Shortcut
Press Shift + Tab to cycle Codex CLI into Plan mode, or type /plan and press Enter to jump straight there. Shift + Tab steps through the collaboration modes in order, so you may need more than one press depending on where you are.
The reason both exist is that they do slightly different jobs. /plan is a direct jump — you name the mode you want. Shift + Tab rotates, which is faster when you are switching back and forth but means you have to look at what mode you landed in.
Shift+Tab is a reserved key
Codex CLI reserves a handful of keys that cannot be reassigned, and the mode cycle is one of them. If you try to bind Shift + Tab to something else in ~/.codex/config.toml, Codex refuses the whole keymap and tells you the key is reserved rather than silently ignoring your config.
The other reserved keys are worth knowing for the same reason — these are the ones you cannot take over:
| Key | What it does |
|---|---|
| Shift + Tab | Cycle collaboration mode — this is Plan mode's key |
| Ctrl + C | Interrupt or quit |
| Ctrl + D | Quit |
| Ctrl + V | Paste an image |
| Esc | Backtrack |
| / ! @ $ | Slash commands, shell command, file paths, connector mentions |
How to leave Plan mode
Keep pressing Shift + Tab. The cycle wraps, so it will come back around to the default mode — there is no separate "exit plan mode" key. If you would rather be explicit about where you land, use the slash command for the mode you want instead of rotating past it.
This is a real difference from some other agents, where the plan toggle is a straight on/off switch. In Codex CLI it is a rotation through a list, so "press it again to turn it off" is not quite right — press it again and you get the next mode, not the previous one.
Shift+Tab means something different in almost every AI CLI
This is the single most confusing key in the category, because the same keystroke has at least three meanings depending on which agent you are in. In Claude Code it is a plain toggle. In Gemini CLI, Cursor CLI and Qwen Code it cycles approval modes. In opencode it switches agents. And several tools do not bind it at all.
So the habit you build in one tool does something unexpected in the next. The cross-tool comparison lays out what Shift + Tab does in each one side by side.
Plan mode and model choice are separate settings
People often reach for Plan mode when what they actually want is a different model or more reasoning. Those are a different control: /model chooses both the model and the reasoning effort, and reasoning effort also has its own keys — Alt + . to raise it and Alt + , to lower it, with Shift + Up and Shift + Down as alternates.
Switching mode does not change your model, and switching model does not put you in Plan mode. If the output is not thinking hard enough, reach for reasoning effort before you reach for the mode cycle.
The rest of the keymap
Shift + Tab is one entry in a much larger keymap — Codex CLI also has Ctrl + J for multi-line prompts, Ctrl + C to exit, Ctrl + T for the transcript, and a full slash-command catalog. The Codex CLI cheat sheet has all of it in one printable page.