PowerMate
PowerMate shows how a MacBook battery ages over time and keeps the Mac awake on purpose — without promising anything macOS doesn't allow.
Challenge
macOS doesn't show how a MacBook battery ages over months: cycle count and capacity sit in System Information as a snapshot, with no history. And keeping the Mac awake usually means caffeinate in the Terminal.
Approach
A menu bar app in the App Sandbox, with no helper tools and no admin rights. Everything it shows or switches can be verified on the system. What macOS doesn't allow — such as stopping the charge — it doesn't claim to do: it reminds you to unplug instead.
Outcome
A free macOS app: battery health and cycle history over up to 365 days, with a forecast of when health reaches 80 and 60 %; power draw in watts and electricity cost; wake modes with a countdown and automation by time, location or battery level. No accounts, no server, no tracking.