Keep Codex running when you close your MacBook lid.

It depends on where Codex is running. The Codex CLI and Codex chats in OpenAI's desktop app work on your Mac, so they stop making progress when a closed lid puts the Mac to sleep. Codex Cloud tasks run in OpenAI's cloud and keep working while your computer sleeps, so they need nothing from your Mac. To keep a local Codex run going with the lid closed and no external monitor, use Clamshell for Mac, a menu bar app that keeps an Apple Silicon MacBook awake with the lid shut and restores normal lid sleep when you disarm it.

Quick answer

Which Codex are you running?

"Codex" covers several products that execute in different places. Only the ones that execute on your Mac care about the lid.

If your repository is already set up for Codex Cloud, sending the overnight task there is the simplest fix: nothing on your laptop has to stay awake. Keep reading if the job needs your local files, tools, credentials or hardware.

Why a local Codex run stops at lid close

1. You close the lidmacOS starts lid sleep, separate from idle sleep.
2. Nothing blocks itA busy agent does not, and neither does caffeinate.
3. Codex stops making progressChild processes, test runners and connections stop too.

Closing a MacBook lid triggers lid sleep, which is separate from idle sleep. An agent that is busy writing code or running tests does not block lid sleep, and neither does caffeinate: it only holds off idle sleep. Once the Mac is asleep, Codex, its child processes, test runners and network connections all stop making progress. Whether the session resumes cleanly on wake depends on what it was doing; the hours in between are lost either way.

OpenAI's desktop app has a Keep this Mac awake setting for Remote hosts, which it describes as preventing sleep when the computer is plugged in and remote access is enabled. OpenAI's own guidance is that a Mac laptop host stays available with the lid open and power connected, and that with the lid closed you should connect an external display as well. That leaves one case uncovered: lid closed, no monitor.

Ways to run Codex locally with the lid closed

• Apple's closed-display mode. Connect an external display, keyboard and mouse, and power. Apple's instructions for a closed-lid laptop say it must be connected to power and using an external keyboard and mouse. Reliable if you own the hardware and stay at your desk.
• sudo pmset -a disablesleep 1. Keeps the Mac awake with the lid closed, but it is a global, admin-level switch with no timer that also applies on battery. See what pmset disablesleep does and how to undo it.
• Clamshell. A menu bar app that overrides lid sleep only while armed. No sudo, no admin rights, no kernel extension, no privileged helper. It uses the unprivileged IOKit clamshell sleep control rather than pmset, and the setting never survives a restart.

Clamshell for Mac keeps an Apple Silicon MacBook awake with the lid closed, no monitor needed. Free for 7 days, then $9.99 once for one Mac.

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Wrap a Codex CLI run so it arms and disarms Clamshell

Clamshell accepts clamshell://arm, clamshell://disarm and clamshell://toggle URLs. This wrapper requests arming before a non-interactive Codex run and requests disarming when the shell exits, so normal lid sleep comes back when the job ends.

set -e
open "clamshell://arm"
trap 'open "clamshell://disarm" || true' EXIT

# codex exec is read-only by default; allow edits in the workspace
codex exec --sandbox workspace-write "run the test suite and fix the failures" \
  2>> codex-progress.log | tee codex-result.md

Read the caveats before you rely on it:

• open only delivers a request. A successful exit does not prove Clamshell armed. It can refuse, for example under serious thermal pressure, or pause while an external display is connected. Check the menu bar state before closing the lid.
• The EXIT trap is best effort. It does not run if the shell is killed or crashes. Disarm from the menu if in doubt.
• Clamshell does not know about Codex. It has no Codex integration and does not detect when an agent finishes. The script is what ends the session.
• Permissions still apply. OpenAI documents that codex exec runs in a read-only sandbox unless you choose a wider one. Pick the least access the job needs; keeping the Mac awake does not approve anything.
• Setapp edition. The Setapp build uses the clamshell-setapp:// scheme instead.

Clamshell also adds Arm, Disarm, Toggle and Status actions to Shortcuts, which you can combine in a shortcut of your own.

Prove that Codex keeps working with the lid closed

Before trusting a long run, spend two minutes on a harmless check.

1. In an interactive Codex session, with the lid open, ask Codex to run this command and approve it:

   for i in {1..12}; do
     date -u '+%Y-%m-%dT%H:%M:%SZ' >> lid-check.txt
     sleep 10
   done

2. Confirm Clamshell is armed and close the lid for the two minutes.
3. Open it and run cat lid-check.txt. Pass: twelve timestamps about ten seconds apart with no gap while the lid was shut.

Fail: a long gap means the run was interrupted; it does not tell you why. Check Clamshell's state, the terminal, and whether Codex was waiting for an approval, fix it with the lid open, and repeat.

If you use Remote from the ChatGPT phone app, do the same check from your phone: after two minutes with the lid closed, ask Codex for the file contents and one fresh timestamp. A connected indicator on its own is not a pass.

Steering a local Codex run from your phone

OpenAI's Remote feature lets the ChatGPT app on iOS or Android control Codex chats on a connected Mac or Windows computer running the ChatGPT desktop app. You set it up from the desktop app, not from the Codex CLI or IDE extension. From the phone you can start or continue chats, answer questions, approve commands and review diffs and test results. The host must stay awake, online and signed in.

Clamshell's part is narrow: with the lid closed, it keeps the host Mac from lid sleep so Remote has something to connect to. It does not make a sleeping Mac reachable, repair a dropped connection, or answer approval prompts on your behalf.

What Clamshell does and does not do

Arming with Option held while you close the lid needs the lid angle sensor in a MacBook Air M2 (2022) or later or a 14-inch or 16-inch MacBook Pro (2021) or later; other Apple Silicon laptops arm from the menu bar. Option-close sessions end when you open the lid; menu and URL arming stays on until you disarm.

Frequently asked questions

Related guides

• Run AI coding agents overnight on a MacBook
• Keep Claude Code running with the lid closed
• Keep a MacBook awake with the lid closed on battery
• Why caffeinate does not work with the lid closed
• Compare Clamshell, Amphetamine, pmset and Apple's setup

Sources checked September 29, 2026: the openai/codex README, OpenAI's Codex Cloud, Remote connections and non-interactive mode docs, and Apple's external display guidance for a closed laptop. Clamshell behavior is described from its app source and FAQ. No new hardware testing was done for this page. Clamshell is an independent app, not affiliated with or endorsed by OpenAI. Codex is a trademark of its owner.