Clamshell for Mac is a menu bar app that keeps an Apple Silicon MacBook awake with the lid closed, with no external display, no sudo, and no admin rights.
Clamshell for Mac keeps the Mac awake with the lid closed while armed. No sudo, no monitor. Free for 7 days, then $9.99 once.
Download free trialClose the lid and the built-in display stays black while coding agents, builds, downloads, and SSH sessions keep running. It is sold at clamshell.dev for $9.99 once after a free 7-day trial, and it is also available on Setapp.
What Clamshell is not
The word "clamshell" means several different things on a Mac, and search results mix them up. This is the app at clamshell.dev. It is not any of the following.
Not Apple's clamshell mode
Apple's clamshell mode keeps a closed MacBook running only while an external display is attached. Without that display, macOS sleeps the Mac as soon as the lid shuts. Clamshell for Mac removes the display requirement. How the two differ.
Not the App Store app of the same name
An unrelated app called Clamshell is listed on the Mac App Store. Clamshell for Mac is sold only at clamshell.dev and on Setapp. Directory listings that describe a "Clamshell" app that puts a Mac to sleep mean that other product.
Not a pmset disablesleep wrapper
Clamshell never runs sudo pmset -a disablesleep 1 and never changes the persistent SleepDisabled setting. Used that command before? The pmset guide shows how to check and undo it.
Not a general keep-awake toolkit
Clamshell does one job: the lid. For timers, triggers, and open-lid sessions, caffeinate or Amphetamine are built for that. The comparison of lid-closed apps says where each fits.
How it works
macOS treats closing the lid as its own sleep trigger, separate from idle sleep. That is why caffeinate does not help once the lid closes. Clamshell addresses the lid trigger directly.
- You close the lidmacOS starts its lid-close sleep path, separate from idle sleep.
- Clamshell is armedIt tells the power manager to skip lid sleep for this session.
- The Mac keeps workingScreen dark, network up, agents and builds still running.
- While armed, Clamshell asks the macOS power manager (
IOPMrootDomain) to skip lid-close sleep through its unprivileged clamshell sleep-state control, and holds aPreventUserIdleSystemSleepassertion so idle sleep does not interrupt work either. - No privileged surface. There is no kernel extension, driver, privileged helper, daemon, or sudo prompt. It is a normal menu bar app.
- The screen stays dark. The built-in display stays black while the lid is closed. Agents can still use the screen for screenshots and desktop interaction during an armed closed-lid session, and the Mac locks when you open the lid.
- The network stays up. Because the Mac is awake, SSH, screen sharing, and syncs keep working.
- External displays pause it. With an external display connected, Clamshell pauses instead of arming.
Ways to arm it
- Option-close: hold ⌥ Option while closing the lid. This session ends when the lid opens. It needs a lid angle sensor, found in the MacBook Air M2 (2022) or later and the 14-inch and 16-inch MacBook Pro (2021) or later.
- Menu bar: arm from the menu on any supported Apple Silicon MacBook. This stays active until you disarm.
- URL or Shortcuts: see automation below. These also stay active until you disarm.
Safety
Thermal safety is always on
Clamshell monitors macOS thermal pressure. At serious or critical pressure it disarms toward normal lid sleep and blocks arming until the Mac has cooled.
Normal sleep comes back
Disarming or quitting restores normal lid-close sleep, retries if needed, and warns you if macOS refuses. The setting is never saved across a restart, so restarting always returns normal lid-close sleep.
Crash recovery
The direct edition can relaunch after an unexpected exit when its crash-recovery agent is permitted.
Battery aware
It works on AC and battery and re-applies itself on every plug or unplug. An optional Disarm on low battery setting, off by default, lets the Mac sleep below a level you choose. See the battery guide.
Keep it ventilated. Leave the closed Mac on a desk, not in a bag or on a bed. Software protection does not replace airflow.
Requirements
Apple Silicon Mac laptops on macOS 14 or later. Intel Macs are not supported. The Option-close gesture needs the lid angle sensor listed above; other Apple Silicon MacBooks arm from the menu bar.
Pricing and channels
- Direct from clamshell.dev: free for 7 days, then $9.99 once for one Mac or $19.99 once for up to 3 Macs. No subscription.
- Refunds: every direct purchase has a 14-day money-back guarantee. See the refund policy.
- Setapp: Clamshell is also available on Setapp.
- Mac App Store: not available there. The App Store app named Clamshell is a different product.
Automation
Clamshell has no native Claude Code, Codex, or other agent integration, and it does not detect running agents. You decide when it is armed. Scripts and automations can drive it through two supported routes.
- URL scheme:
clamshell://arm,clamshell://disarm, andclamshell://toggle. From a terminal,open "clamshell://arm"sends the request. It is asynchronous, so check the menu bar state before closing the lid. - Shortcuts: Arm Clamshell, Disarm Clamshell, Toggle Clamshell, and Clamshell Status actions.
open "clamshell://arm"
trap 'open "clamshell://disarm" || true' EXIT
# your long-running task
claude -p "run the test suite and fix the failures"The full agent workflow, including a phone Remote Control setup and a test that proves work continues with the lid closed, is in how to keep Claude Code running with the lid closed. For Codex specifically, see keeping Codex running with the lid closed, and for unattended runs, running AI agents overnight on a MacBook.
Who it is for
Clamshell is for people who want a MacBook to keep working after the lid closes and do not want to carry a monitor or manage a system-wide Terminal switch: developers running Claude Code, Codex, or Cursor, long builds and test suites, large downloads, and Macs reached over SSH or screen sharing. If the lid stays open, a free command like caffeinate is enough. If you want a broad keep-awake toolkit or automatic agent detection, compare the options in LidRun vs Amphetamine vs Clamshell and the Amphetamine alternative guide. For the general question, start with how to keep a MacBook awake with the lid closed.
Frequently asked questions
Is Clamshell the same as Apple's clamshell mode?
No. Apple's clamshell mode is built into macOS and keeps a MacBook running with the lid closed only while an external display is attached. Clamshell for Mac is a separate menu bar app that keeps the MacBook awake with the lid closed and no display attached.
Is Clamshell on the Mac App Store?
No. Clamshell for Mac is available from clamshell.dev and on Setapp. An App Store app with the same name is unrelated.
Does Clamshell use pmset disablesleep?
No. Clamshell does not use pmset disablesleep and does not change the persistent SleepDisabled setting. While armed it uses the unprivileged IOKit lid sleep-state control plus an idle-sleep assertion, and it needs no sudo or administrator password.
Is it safe to run a MacBook with the lid closed using Clamshell?
Clamshell's thermal safety is always on: serious or critical thermal pressure disarms it toward normal lid sleep and blocks arming until the Mac cools. The setting never survives a restart, and an optional low-battery cutoff can let the Mac sleep before the battery runs flat. Keep the Mac ventilated; software protection does not replace airflow.
Does Clamshell detect Claude Code or other agents automatically?
No. Clamshell has no agent auto-detection and no native Claude Code or Codex integration. You arm it from the menu bar, with the Option-close gesture, with the clamshell://arm URL, or with its Shortcuts actions.
How much does Clamshell cost?
The direct version is free for 7 days, then $9.99 once for one Mac or $19.99 once for up to 3 Macs. There is no subscription, and every direct purchase has a 14-day money-back guarantee. It is also available on Setapp.
Sources: this page describes Clamshell's own behavior as documented on the homepage FAQ and in the existing guides. Clamshell is the publisher of this page. Apple, Mac, MacBook, and other product names are trademarks of their respective owners.