Talking about native Mac development, SwiftUI and AppKit, and building apps with Claude Code.
No journal, it recomputes. The helper only touches one system power setting, and its safe value is known, so at boot it writes that value back before anything else, and the app has to ask for a hold again. Keeping the helper’s surface that small is what made a journal unnecessary. The trimmed trailing JSONL line is a nice trick, I’ll borrow it for my own session logs.
The generation counter is the detail I would have missed. I went the XPC route for a small root helper in one of my Mac apps, and what bit me there was the mirror of your HOST_PID check: the helper has to notice when the app goes away and undo what it changed, so it restores state when the client drops and again at boot. Does your core only exit when the host dies, or does it also tidy up work it left half done, like a session file mid-write or LSP children still running?
Curated Topics groups are the part I keep relearning. An alphabetical symbol list only helps someone who already knows the name they want. One habit that has worked for me as a solo Mac developer: write the summary line in the same commit as the symbol, as you say, and let CI fail on broken symbol links. It keeps the docs from drifting between releases.
