I kept starting something long — an agent working through a task, a build, a render — and then not being able to leave the desk. Locking the Mac is the obvious move, but then the screen is gone and some of the work goes with it. Leaving it unlocked meant leaving my screen readable to an open-plan office. So Cuukit does the temporary version. One click covers every display behind a four-digit PIN, holds the keyboard so only those digits get through, and keeps the Mac awake until you come back. At the moment macOS would have blanked the screen anyway, the cover goes fully dark. The browser case is the one I could actually measure. Lock a Mac and Chrome marks every tab hidden — frames stop, timers fall to one tick a second, and an agent driving a real page dies with it. Under the cover the same tab kept drawing at full rate across six runs. The harness is public at cuukit.com/measure if you want to run it on your own Mac. Two limits worth saying out loud. This is a privacy cover over a live session, not a replacement for the login window — the login window is stronger and the site says so. And it does not help agents that read the screen itself: a desktop-use agent sees the cover, not your apps. That is the same property that hides it from the room, so it cannot really be otherwise. Free, Apple silicon, no account, no network access at all. Happy to answer anything.

Cuukit Screen Lid

Keep your AI agents running while you step away

Keep your AI agents running while you step away