Fleet power watch

One job: tell Lacy before the laptop sleeps and takes the whole fleet with it.

scripts/fleet-power-watch.ts, run by launchd every 5 minutes, reads pmset -g batt and Slack-DMs one line when the Mac is on battery and getting low. Once below 20%, once below 10%, nothing more until it is back on AC.

Why it exists (LAC-4574)

Every agent run, every routine and every client-facing watch in this company executes on one laptop. On 2026-10-16 that laptop slept at 1% battery:

2026-10-16 07:31:24 -0400 Sleep  Entering Sleep state due to 'Low Power Sleep' ... (Charge:1%)
2026-10-16 09:30:51 -0400 Wake   Wake from Hibernate [CDNVA] : due to charger/UserActivity

Two hours. Zero activity_log rows, zero heartbeat_runs, the 12:00Z Doug store watch slot never evaluated, and six runs that morning died setup_failed: Legacy controller lease lost and parked their issues silently. Nothing said any of it. The gap was found afterwards, by reading pmset -g log.

The stranded-work watch names this as its own known gap: it watches the board, not the machine. This is the machine half.

The alert

Mac at 8% on battery, about 24 min left. Below ~5% it sleeps and the whole fleet
stops: no routines, no agent runs, no store watch. Plug in.

The number first, because that is the decision. What stops, because "low battery" is something the menu bar already says and nobody acts on. The action last, because it is one word of work.

The estimate is dropped rather than invented when pmset does not have one, which is normal for a minute or two after unplugging.

One discharge, two messages

Battery	On battery	Sent
21%	yes	nothing
18%	yes	first DM
14%	yes	nothing
8%	yes	second DM
3%	yes	nothing
any	plugged in	nothing, and the two warnings rearm

AC is the only thing that rearms it, so a long discharge produces two messages rather than twenty. Crossing both thresholds between two checks (the Mac was asleep, or this was installed mid-discharge) spends both and sends one message, not two.

A machine with no battery reports as permanently fine, so the same file is safe on the Hetzner box (LAC-4279).

Run it by hand

bun scripts/fleet-power-watch.ts                    # print, do not DM
bun scripts/fleet-power-watch.ts --notify            # print and DM
bun scripts/fleet-power-watch.ts --state /tmp/p.json # scratch state

Exit codes: 0 power is fine, 1 running low, 2 could not read the power state (pmset missing, or output this does not understand). 2 never spends a warning. Silence on AC is the designed output, same contract as the store watch, its freshness check and the stranded-work watch.

Needs POWER_WATCH_SLACK_TOKEN and POWER_WATCH_SLACK_CHANNEL to DM.

Schedule

~/Library/LaunchAgents/com.buildandserve.fleet-power-watch.plist, StartInterval 300, log at ~/.paperclip/logs/fleet-power-watch.log, state at ~/.paperclip/power-watch-state.json.

launchctl bootout gui/$UID/com.buildandserve.fleet-power-watch 2>/dev/null
launchctl bootstrap gui/$UID ~/Library/LaunchAgents/com.buildandserve.fleet-power-watch.plist
launchctl kickstart -p gui/$UID/com.buildandserve.fleet-power-watch

The plist, if it ever needs rebuilding:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>com.buildandserve.fleet-power-watch</string>
  <key>ProgramArguments</key>
  <array>
    <string>/bin/sh</string>
    <string>-c</string>
    <string>cd /Users/lacy/repo/buildandserve &amp;&amp; POWER_WATCH_SLACK_TOKEN=$(/opt/homebrew/bin/jq -r '.channels.slack.botToken' /Users/lacy/.openclaw/openclaw.json) POWER_WATCH_SLACK_CHANNEL=U3XC80UUQ /opt/homebrew/bin/bun scripts/fleet-power-watch.ts --notify</string>
  </array>
  <key>StartInterval</key>
  <integer>300</integer>
  <key>RunAtLoad</key>
  <true/>
  <key>ProcessType</key>
  <string>Background</string>
  <key>StandardOutPath</key>
  <string>/Users/lacy/.paperclip/logs/fleet-power-watch.log</string>
  <key>StandardErrorPath</key>
  <string>/Users/lacy/.paperclip/logs/fleet-power-watch.log</string>
</dict>
</plist>

launchd, not a Paperclip routine, because Paperclip is downstream of the battery. A routine that watches the battery dies with it.

Deliberately not here

No battery-health history and no graph. The decision is binary: plug in or do not.
No automatic pausing of routines, and no attempt to keep working through sleep. Both are much larger jobs and neither is what was missing.
No "you're back on AC" message. Lacy plugged the cable in; he knows.
No configurable thresholds. Two numbers, in the source, with tests.

Delete it when

The fleet no longer runs on one laptop. LAC-3840 and LAC-3841 moved the Keepsake worker off the Mac for this exact reason, and LAC-4279 is the server that would finish the job. When nothing client-facing depends on this battery, this file and its plist go.

Known gaps

It warns about battery, not about the other ways the Mac goes away: lid closed on AC, a reboot, Wi-Fi dropping. Those stay invisible.
pmset's time estimate is its own guess and swings under changing load. The percentage is the number to trust.