A pet is idle 99% of the time, so idle is the only number that matters. While measuring battery I found my own behaviour loop calling screen capture and OCR on every tick, forever, with no way to turn it off.

The fix was not a time cache - that returns stale frames when the screen does change. It was a positive signal that nothing changed: no input and no active app switch since the last capture, plus a thumbnail comparison.

The part I still cannot do honestly is quote a watts-per-process number: measuring that on Apple Silicon needs sudo, and powermetrics gives an estimate. If anyone has a method they trust for a background app, I would like to hear it.

Mewmori keeps facts about you rather than a chat log: your name, what you work on, what kept you busy last week. A week later it brings one of them up by itself.

Deciding what belongs in that list turned out to be the hardest part. Names and projects are obvious. Moods are tempting and, I think, a mistake. Anything about health I ruled out early.