It Can Die in Its Sleep — Self-Healing launchd Jobs with Multi-Slot Firing and a Done-Marker

My previous piece, " Making a launchd Job Unload Itself ," built a job that runs exactly once and then unloads itself. This time it's the mirror image: a pattern designed around the assumption that the job will die mid-run — it fires several slots a day and delivers "retry until it succeeds, then quit immediately on success." Every morning I hand Claude Code the task of updating my Obsidian Vault, and it kept dying partway through — killed by macOS sleep, no network on wake, or a claude timeout. Instead of trying to prevent every failure perfectly, I decided "it can die overnight as long as it's done by the time I wake up" was the more realistic goal, and I redesigned around that. The problem: "started but didn't finish" piles up silently There are three ways a launchd job fails to run to completion. Lid-close sleep (on battery) — caffeinate -s only works on AC power. On battery, the job freezes the instant you close the lid, and gets reaped by timeout after wake. No network — right after wake, WiFi isn't connected yet. git push and claude's API calls time out. claude timeout — an ingest that chews through 28 hours of conversation logs doesn't fit in a single slot and times out (this happened three days in a row, 2026-06-11 to 13). All three can look like "the job started, exit code 0," so you notice late. Overall design: 4 slots + a done-marker The fix is simple: stuff multiple StartCalendarInterval entries into the plist, and at the top of the script check "if today's run already succeeded, exit 0 immediately." <!-- com.shun.vault-auto-ingest.plist (StartCalendarInterval excerpt) --> <key> StartCalendarInterval </key> <array> <dict> <key> Hour </key><integer> 4 </integer><key> Minute </key><integer> 55 </integer> </dict> <dict> <key> Hour </key><integer> 8 </integer><key> Minute </key><integer> 20 </integer> </dict> <dict> <key> Hour </key><integer> 10 </integer><key> Minute </key><integer> 45 </integer> </dict> <dict> <key> Hour </key><integer> 12 </integer><key>