What it does
Restricts shaking to times when Apple Music is actively playing.
How it works
Shake It On observes the Music.app player state (via DistributedNotificationCenter) and a one-shot AppleScript probe at startup. When Music is playing, the condition is satisfied.
Where to find it
Settings → Only Shake If → Audio is playing.
When to use it
Pair with another condition like 'CPU above threshold' to make Shake It On a smart 'something's actually happening' detector.