Guide · Clamshell mode

Keep a MacBook awake, lid closed (clamshell mode)

Shut the lid and your MacBook goes to sleep — that is the default, and it is usually what you want. But when a build, a download, or an AI coding agent is still running, closing the lid can stop the work dead. This guide explains why the lid triggers sleep, what real clamshell mode actually requires, and how Perked keeps your Mac awake with the lid closed — without an external display, extra cables, or a risky system-wide override.

What closing the lid actually does

On a MacBook, closing the lid is a hardware signal to sleep. By default macOS suspends the whole system: the CPU idles, the display and keyboard power down, network connections drop, and anything mid-flight is paused until you open the lid again. It does not matter whether a long job is running — the lid switch wins. That is great for battery and for tossing the laptop in a bag, but it is exactly the wrong behavior when you want a task to keep going on your desk.

What true clamshell mode requires

Apple does support running a MacBook with the lid shut — it is called clamshell (or closed-display) mode. But the built-in version has strict conditions. All of these must be true at once:

• An external display. The Mac needs a monitor connected, because clamshell mode is designed to drive an external screen, not to run headless.
• An external keyboard or mouse. A USB or Bluetooth input device (or a connected dock) is required so you can wake and control the Mac with the lid down.
• Power. On most models the Mac must be plugged in; on battery, closing the lid sleeps it regardless.

If you just want an overnight build or an agent run to continue — with nothing plugged in but the charger — the built-in clamshell mode is more setup than the job deserves.

Keep it cool: ventilation and heat

A closed MacBook running under load has less room to shed heat — the lid sits against the keyboard, and a soft surface like a bed or sofa can block the vents. Give it a hard, flat surface with airflow around it, and ideally raise it on a stand so air can move underneath. macOS will throttle the CPU to protect the hardware if it gets too hot, which slows the very job you are trying to finish. Keeping the machine cool is not just about safety; it is about the run actually completing on time.

The manual routes, and their limits

Before reaching for an app, it is worth knowing the built-in options and where they fall short:

• pmset disablesleep 1 flips a system-wide flag that stops the Mac from sleeping at all — including on lid close. It needs an admin password, it is easy to forget you left it on, and because it disables every kind of sleep it can quietly drain the battery or let a laptop overheat. Turning it off again is a second command you have to remember.
• caffeinate is friendlier, but it only prevents idle sleep — it does not, on its own, defeat the lid-close sleep signal. Close the lid and the Mac still sleeps. It also stays on for whatever you tell it, whether or not real work is happening.
• Utility apps. General keep-awake utilities can hold the Mac awake, and some offer a lid-closed option — but many still expect you to toggle it by hand before every run and off afterwards, and they keep the Mac awake indiscriminately rather than only while a job is running.

Where Perked fits

Perked is a macOS menu-bar app built for exactly this. Its clamshell mode keeps your Mac awake with the lid closed — and, unlike the built-in one, it does not need an external display, keyboard, or mouse. You approve the permission once; after that, closing the lid no longer stops your work.

It is also tied to what you are doing rather than left running forever. Perked auto-detects coding agents like Claude Code and Cursor and stays awake only while they run, it can require AC power or a battery threshold you set, and if it ever quits or crashes with the lid down, your Mac goes back to sleeping normally on its own — so it can never get stuck awake.

It is a one-time purchase from €1 — currently €1, and whatever you pay is locked in for good.

Lid-closed FAQ

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