diff --git a/deploy/waving-hands-backup.sh b/deploy/waving-hands-backup.sh
index fe9dbe4..8711cac 100755
--- a/deploy/waving-hands-backup.sh
+++ b/deploy/waving-hands-backup.sh
@@ -14,9 +14,14 @@ LOG="/var/log/waving-hands/backup.log"
 STAMP=$(date +%Y-%m-%d)
 mkdir -p "$(dirname "$LOG")"
 CRON_URL=$(cat /root/.waving-hands-sentry-cron 2>/dev/null || true)
+# One check-in, when the run ends, carrying its duration: a start and a
+# finish sent seconds apart can reach Sentry in either order, and a start
+# that lands second is never closed. A run that never ends sends nothing,
+# and Sentry marks the night missed.
+START=$SECONDS
 checkin() {
   [ -n "$CRON_URL" ] && curl -sf -o /dev/null -X POST -H "Content-Type: application/json" \
-    -d "{\"status\":\"$1\",\"monitor_config\":{\"schedule\":{\"type\":\"crontab\",\"value\":\"$SCHEDULE\"},\"checkin_margin\":30,\"max_runtime\":10,\"timezone\":\"UTC\"}}" \
+    -d "{\"status\":\"$1\",\"duration\":$((SECONDS - START)),\"monitor_config\":{\"schedule\":{\"type\":\"crontab\",\"value\":\"$SCHEDULE\"},\"checkin_margin\":30,\"max_runtime\":10,\"timezone\":\"UTC\"}}" \
     "$CRON_URL" || true
 }
 
@@ -27,7 +32,6 @@ fi
 
 {
   echo "=== $(date -Is) backup start"
-  checkin in_progress
   if rclone sync "$SRC" "spaces:$BUCKET/$PREFIX/current" --exclude 'rollup.jsonl' 2>&1 &&
      rclone copy "$SRC" "spaces:$BUCKET/$PREFIX/snapshots/$STAMP" 2>&1; then
     checkin ok
diff --git a/deploy/waving-hands-rollup.sh b/deploy/waving-hands-rollup.sh
index c035d57..977d440 100755
--- a/deploy/waving-hands-rollup.sh
+++ b/deploy/waving-hands-rollup.sh
@@ -16,13 +16,17 @@ DAY="${1:-$(date -u -d 'yesterday' +%Y-%m-%d)}"
 SCHEDULE="12 0 * * *"
 CRON_URL=$(cat /root/.waving-hands-sentry-cron-rollup 2>/dev/null || true)
 # The check-in carries the schedule: Sentry keeps a monitor only once told its shape.
+# One check-in, when the run ends, carrying its duration: a start and a
+# finish sent seconds apart can reach Sentry in either order, and a start
+# that lands second is never closed. A run that never ends sends nothing,
+# and Sentry marks the night missed.
+START=$SECONDS
 checkin() {
   [ -n "$CRON_URL" ] && curl -sf -o /dev/null -X POST -H "Content-Type: application/json" \
-    -d "{\"status\":\"$1\",\"monitor_config\":{\"schedule\":{\"type\":\"crontab\",\"value\":\"$SCHEDULE\"},\"checkin_margin\":30,\"max_runtime\":10,\"timezone\":\"UTC\"}}" \
+    -d "{\"status\":\"$1\",\"duration\":$((SECONDS - START)),\"monitor_config\":{\"schedule\":{\"type\":\"crontab\",\"value\":\"$SCHEDULE\"},\"checkin_margin\":30,\"max_runtime\":10,\"timezone\":\"UTC\"}}" \
     "$CRON_URL" || true
 }
 mkdir -p "$(dirname "$LOG")"
-checkin in_progress
 if python3 - "$DAY" "$OUT" <<'PY' >> "$LOG" 2>&1
 import collections, datetime, glob, gzip, json, os, re, shutil, sys
 day, out = sys.argv[1], sys.argv[2]
@@ -72,6 +76,6 @@ rows.sort(key=lambda r: r["day"])
 with open(out + ".tmp", "w") as fh:
     for r in rows: fh.write(json.dumps(r) + "\n")
 os.replace(out + ".tmp", out)
-print("%s rolled: %d people, %d requests, %d rooms" % (day, len(hips), human, created))
+print("%s rolled: %d people, %d requests, %d rooms" % (day, len(t["addresses"]), t["human"], created))
 PY
 then checkin ok; else checkin error; fi