Always on, lid shut: why UnIdle still lets your Mac sleep

"Always" sounds like it should mean always. With the lid open, it does. With the lid shut on battery, UnIdle deliberately holds off sleep only while an agent is working — and this is why.

The questionIf UnIdle is set to Always, why does my Mac sleep when I shut the lid?

The short answerA shut Mac with nothing running has no reason to stay on — only a reason to overheat and drain the battery.

What UnIdle doesWith the lid shut on battery, it keeps the Mac running only while an agent is actually working, in every mode.

The three modes

Off — UnIdle stays out of the way, and your Mac sleeps on its normal schedule.

AI Active — the Mac stays awake only while an AI coding agent is working, then sleeps as usual.

Always — the Mac stays awake, agent or not, until you switch it off. Useful when you're watching something long, or running your own scripts.

What a shut lid changes

With the lid open, staying awake costs little: the screen can still dim, you're probably nearby, and the Mac has airflow. With the lid shut, it's often in a bag. There's no airflow, nobody watching, and nothing on screen.

A shut Mac doing real work — finishing an agent run — is worth that cost. A shut Mac doing nothing isn't. It just runs warm and drains the battery until the battery floor finally stops it.

The rule

When you close the lid on battery, UnIdle Pro keeps the Mac running only while an agent is actually working. The moment the work is done, sleep comes back — even in Always mode.

Note: This only applies to a shut lid on battery. With the lid open, Always keeps the Mac awake exactly as before. And plugged in, macOS honours UnIdle's keep-awake request with the lid shut too — that's the desk setup, where staying on is the point.

Warning: The Terminal route, sudo pmset -a disablesleep 1, has no rule like this. It keeps a shut Mac running until you remember to turn it back off — agent or not. See the 23:52 problem.

Where to find it

In UnIdle, open Settings › Power › Prevent sleep on lid-close (battery). The note under the switch says the same thing as this article: it only holds a shut lid while an agent is working.

Where UnIdle fits

Keeping a Mac awake is easy. Knowing when to is the hard part, and that's what UnIdle is for:

It knows when an agent is working, and when it's done — no timers to guess.
Lid shut on battery, it holds sleep off only for real work, then hands it straight back.
If UnIdle ever quits mid-run, the helper turns sleep back on at once.

Download freeLid shut on battery is a Pro feature — $12 once, with a 14-day free trial.