diff --git a/.claude/skills/gamehall-visitors/SKILL.md b/.claude/skills/gamehall-visitors/SKILL.md
index 349aaa6..8823b50 100644
--- a/.claude/skills/gamehall-visitors/SKILL.md
+++ b/.claude/skills/gamehall-visitors/SKILL.md
@@ -23,7 +23,7 @@ name (the sslip test address is left out) and prints:
   own digest (/wizwar-visitors) lists gamehall.kestrelsnest.social among
   its referrers.
 - **last 7 days** from `/var/lib/gamehall/rollup.jsonl`, written nightly
-  at 00:05 UTC by `gamehall-rollup.sh` for the day before (counts only,
+  at 00:12 UTC by `gamehall-rollup.sh` (run by `hall-nightly.sh`) for the day before (counts only,
   no addresses).
 
 ## Read it
diff --git a/CONVENTIONS.md b/CONVENTIONS.md
index aec8699..44c3a41 100644
--- a/CONVENTIONS.md
+++ b/CONVENTIONS.md
@@ -198,8 +198,9 @@ Every game gets the same tools, installed by `deploy.sh` on every deploy:
   the rollup's last week, the backup's last word, the box's vitals.
 - `<slug>-rollup.sh` nightly at 00:12 UTC: one JSON line a day of counts,
   no addresses. `<slug>-backup.sh` nightly at 07:23 UTC: rclone to the
-  shared Space, mirror plus dated snapshots pruned after 90 days. Both check
-  in with Sentry Crons so a missed night is noticed.
+  shared Space, mirror plus dated snapshots pruned after 90 days. On the
+  shared host the hall's `hall-nightly.sh` runs both for every game and
+  checks in with Sentry Crons once for all, so a missed night is noticed.
 - The reports desk (skill `<slug>-reports`): `pull-reports.sh` mirrors the
   desk to the Desktop with a digest; `report-reply.sh <ip> <id> <status>
   "text"` answers with `resolved`, `by-design` or `open`. A fix goes live
diff --git a/README.md b/README.md
index 9123ee5..fa302fb 100644
--- a/README.md
+++ b/README.md
@@ -115,3 +115,11 @@ nightly rollup line in /var/lib/gamehall/rollup.jsonl. The skill
 `gamehall-visitors` reads them. A new game on the shared host is added to
 `GAMES` in `gamehall/ops/traffic.py` so the digest counts the people the
 hall sends it.
+
+The hall also keeps the night on the shared host: `hall-nightly.sh rollup`
+at 00:12 UTC and `hall-nightly.sh backup` at 07:23 UTC (`gamehall.cron`)
+run the hall's own rollup and every game's rollup and backup found in
+/usr/local/bin, and check in with Sentry Crons once for each job, monitors
+`hall-rollup` and `hall-backup` in the `gamehall` project, from the URLs in
+/root/.hall-sentry-cron-rollup and /root/.hall-sentry-cron-backup. A game's
+own cron file and check-ins are for a box of its own.
diff --git a/gamehall/deploy.sh b/gamehall/deploy.sh
index b0b800f..ceb1ea7 100755
--- a/gamehall/deploy.sh
+++ b/gamehall/deploy.sh
@@ -21,6 +21,8 @@ ssh "root@$HOST" '
   # The counting tools: installed on every publish so the live copies are the repo copies.
   install -m 755 /tmp/gamehall-ops/gamehall-visitors.sh /usr/local/bin/gamehall-visitors.sh
   install -m 755 /tmp/gamehall-ops/gamehall-rollup.sh /usr/local/bin/gamehall-rollup.sh
+  # The nightly job that runs the rollup and backup of every game here and checks in once for all.
+  install -m 755 /tmp/gamehall-ops/hall-nightly.sh /usr/local/bin/hall-nightly.sh
   install -m 644 -D /tmp/gamehall-ops/traffic.py /usr/local/lib/gamehall/traffic.py
   install -m 644 /tmp/gamehall-ops/gamehall.cron /etc/cron.d/gamehall
   # The hall-wide notice every game serves at /hall/announcement.json.
diff --git a/gamehall/ops/gamehall-rollup.sh b/gamehall/ops/gamehall-rollup.sh
index 08f43b9..fef0c2f 100755
--- a/gamehall/ops/gamehall-rollup.sh
+++ b/gamehall/ops/gamehall-rollup.sh
@@ -4,7 +4,7 @@
 # and the people sent on to each game here). Counts only: no addresses are
 # kept, so the trend outlives the self-rotating access log.
 #   gamehall-rollup.sh [YYYY-MM-DD]   (default: yesterday, UTC)
-#   Cron: /etc/cron.d/gamehall, installed by gamehall/deploy.sh.
+#   Run nightly by hall-nightly.sh rollup (/etc/cron.d/gamehall).
 set -u
 OUT="/var/lib/gamehall/rollup.jsonl"
 LOG="/var/log/gamehall/rollup.log"
diff --git a/gamehall/ops/gamehall.cron b/gamehall/ops/gamehall.cron
index e1dbe2e..eaec068 100644
--- a/gamehall/ops/gamehall.cron
+++ b/gamehall/ops/gamehall.cron
@@ -1,2 +1,4 @@
-# Kestrel's Hall: nightly rollup of yesterday's counts. UTC.
-5 0 * * * root /usr/local/bin/gamehall-rollup.sh
+# Kestrel's Hall: the nightly work of every game on this host, and the hall's own count. UTC.
+# The times are also SCHEDULE in hall-nightly.sh, which tells Sentry to expect them; change both.
+12 0 * * * root /usr/local/bin/hall-nightly.sh rollup
+23 7 * * * root /usr/local/bin/hall-nightly.sh backup
diff --git a/gamehall/ops/hall-nightly.sh b/gamehall/ops/hall-nightly.sh
new file mode 100755
index 0000000..9f84171
--- /dev/null
+++ b/gamehall/ops/hall-nightly.sh
@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+# The hall's nightly work for every game on this host, with one Sentry Crons
+# check-in for the lot: the rollups just after midnight, the backups at
+# breakfast. Each game's own script does its work and says by its exit
+# status whether it managed; the games are found by their scripts in
+# /usr/local/bin, so a game deployed here is covered without being listed.
+#   hall-nightly.sh rollup|backup
+#   Cron: /etc/cron.d/gamehall, installed by gamehall/deploy.sh. SCHEDULE
+#   below must match it, because Sentry is told the same shape.
+#   Sentry Crons check-in: /root/.hall-sentry-cron-<job> holds the check-in
+#   URL (absent = no check-ins).
+set -u
+JOB="${1:-}"
+case "$JOB" in
+  rollup) SCHEDULE="12 0 * * *" ;;
+  backup) SCHEDULE="23 7 * * *" ;;
+  *) echo "usage: hall-nightly.sh rollup|backup" >&2; exit 2 ;;
+esac
+LOG="/var/log/gamehall/nightly.log"
+CRON_URL=$(cat "/root/.hall-sentry-cron-$JOB" 2>/dev/null || true)
+# One check-in, when the run ends, carrying its duration and the schedule
+# (Sentry keeps a monitor only once told its shape). A start and a finish
+# sent seconds apart can reach Sentry in either order, and a start that lands
+# second is never closed. A run that never ends sends nothing, and Sentry
+# marks the night missed.
+START=$SECONDS
+checkin() {
+  [ -n "$CRON_URL" ] && curl -sf -o /dev/null -X POST -H "Content-Type: application/json" \
+    -d "{\"status\":\"$1\",\"duration\":$((SECONDS - START)),\"monitor_config\":{\"schedule\":{\"type\":\"crontab\",\"value\":\"$SCHEDULE\"},\"checkin_margin\":30,\"max_runtime\":30,\"timezone\":\"UTC\"}}" \
+    "$CRON_URL" || true
+}
+mkdir -p "$(dirname "$LOG")"
+
+# The hall's own count first, then each game's script, in name order.
+scripts=()
+[ "$JOB" = rollup ] && scripts+=(/usr/local/bin/gamehall-rollup.sh)
+for s in /usr/local/bin/*-"$JOB".sh; do
+  [ "$s" = /usr/local/bin/gamehall-rollup.sh ] || scripts+=("$s")
+done
+failed=()
+for s in "${scripts[@]}"; do
+  name=$(basename "$s" "-$JOB.sh")
+  "$s" || failed+=("$name")
+done
+if [ ${#failed[@]} -eq 0 ]; then
+  echo "$(date -Is) $JOB: ${#scripts[@]} done" >> "$LOG"
+  checkin ok
+else
+  echo "$(date -Is) $JOB: ${#scripts[@]} run, failed: ${failed[*]}" >> "$LOG"
+  checkin error
+  exit 1
+fi
diff --git a/template/deploy/README.md b/template/deploy/README.md
index 1d2bab3..995ff8c 100644
--- a/template/deploy/README.md
+++ b/template/deploy/README.md
@@ -46,9 +46,11 @@ A fresh host, when one is needed: `doctl compute droplet create hall --region ny
 
 ## Operations scripts on the droplet
 
-`deploy.sh` installs these to /usr/local/bin, the `traffic.py` they share to
-/usr/local/lib/__SLUG__, and the cron file to /etc/cron.d/__SLUG__ on every
-deploy, so the live copies are the repo copies:
+`deploy.sh` installs these to /usr/local/bin and the `traffic.py` they share
+to /usr/local/lib/__SLUG__ on every deploy, so the live copies are the repo
+copies. The cron file goes to /etc/cron.d/__SLUG__ only on a box of the game's
+own: on the hall's shared host, `hall-nightly.sh` (in the kit's `gamehall/ops`)
+runs every game's rollup and backup from /etc/cron.d/gamehall.
 
 - `__SLUG__-visitors.sh [day]`: who is here now and who came that day.
 - `__SLUG__-pulse.sh`: the weekly health check (service, errors, rollup
@@ -62,10 +64,13 @@ deploy, so the live copies are the repo copies:
   wizwar droplet; until then it logs "skipped".
 
 Errors from the game server go to Sentry, project `__SLUG__` in the
-locallygrownnet organisation; the DSN is in the unit file. The nightly rollup
-and backup check in with Sentry Crons when /root/.__SLUG__-sentry-cron-rollup
-and /root/.__SLUG__-sentry-cron hold their check-in URLs (the ingest
-URL with the project's cron path and public key), so a missed night is noticed.
+locallygrownnet organisation; the DSN is in the unit file. On the shared host
+the hall's nightly job checks in with Sentry Crons once for every game's
+rollup and once for every backup (monitors `hall-rollup` and `hall-backup` in
+the `gamehall` project), and each game's script reports by its exit status.
+A game on its own box checks in for itself when /root/.__SLUG__-sentry-cron-rollup
+and /root/.__SLUG__-sentry-cron hold check-in URLs (the ingest URL with the
+project's cron path and public key); absent, it sends nothing.
 
 To have every new issue, regression and reappearance posted to Slack the way
 wizwar's are, run `deploy/sentry-slack-alert.sh [#channel]` once from your own
diff --git a/template/deploy/__SLUG__-backup.sh b/template/deploy/__SLUG__-backup.sh
index a69257b..2f0514b 100755
--- a/template/deploy/__SLUG__-backup.sh
+++ b/template/deploy/__SLUG__-backup.sh
@@ -5,6 +5,8 @@
 # Ledgers are append-only JSONL; the game server never needs stopping.
 # Sentry Crons check-in: /root/.__SLUG__-sentry-cron holds the check-in
 # URL (absent file = no check-ins). SCHEDULE must match /etc/cron.d/__SLUG__.
+# On a host the hall shares, hall-nightly.sh runs this and checks in once
+# for every game, so the file is absent and the exit status is the word.
 set -u
 SCHEDULE="23 7 * * *"
 BUCKET="kestrel-wizwar-backups" # the hall's shared Space, named for its first tenant
@@ -27,9 +29,10 @@ checkin() {
 
 if [ ! -s /root/.config/rclone/rclone.conf ]; then
   echo "$(date -Is) skipped: rclone is not configured" >> "$LOG"
-  exit 0
+  exit 1
 fi
 
+status=0
 {
   echo "=== $(date -Is) backup start"
   if rclone sync "$SRC" "spaces:$BUCKET/$PREFIX/current" --exclude 'rollup.jsonl' 2>&1 &&
@@ -37,6 +40,7 @@ fi
     checkin ok
   else
     checkin error
+    status=1
   fi
   CUTOFF=$(date -d "90 days ago" +%Y-%m-%d)
   rclone lsf "spaces:$BUCKET/$PREFIX/snapshots/" --dirs-only 2>/dev/null | \
@@ -49,3 +53,4 @@ fi
   done
   echo "=== $(date -Is) backup done"
 } >> "$LOG" 2>&1
+exit $status
diff --git a/template/deploy/__SLUG__-rollup.sh b/template/deploy/__SLUG__-rollup.sh
index 6e476a0..cc2acc3 100755
--- a/template/deploy/__SLUG__-rollup.sh
+++ b/template/deploy/__SLUG__-rollup.sh
@@ -8,7 +8,9 @@
 #   Cron: /etc/cron.d/__SLUG__, installed by deploy.sh; SCHEDULE below
 #   must match it, because the Sentry monitor is told the same shape.
 #   Sentry Crons check-in: /root/.__SLUG__-sentry-cron-rollup holds the
-#   check-in URL (absent = no check-ins).
+#   check-in URL (absent = no check-ins). On a host the hall shares,
+#   hall-nightly.sh runs this and checks in once for every game, so the
+#   file is absent and the exit status is the word.
 set -u
 OUT="/var/lib/__SLUG__/rollup.jsonl"
 LOG="/var/log/__SLUG__/rollup.log"
@@ -78,4 +80,4 @@ with open(out + ".tmp", "w") as fh:
 os.replace(out + ".tmp", out)
 print("%s rolled: %d people, %d requests, %d rooms" % (day, len(t["addresses"]), t["human"], created))
 PY
-then checkin ok; else checkin error; fi
+then checkin ok; else checkin error; exit 1; fi
diff --git a/template/deploy/deploy.sh b/template/deploy/deploy.sh
index bb754e1..248c382 100755
--- a/template/deploy/deploy.sh
+++ b/template/deploy/deploy.sh
@@ -43,7 +43,11 @@ ssh "root@$HOST" '
   install -m 755 /opt/__SLUG__/app/deploy/__SLUG__-rollup.sh /usr/local/bin/__SLUG__-rollup.sh
   install -m 755 /opt/__SLUG__/app/deploy/__SLUG__-backup.sh /usr/local/bin/__SLUG__-backup.sh
   install -m 644 -D /opt/__SLUG__/app/deploy/traffic.py /usr/local/lib/__SLUG__/traffic.py
-  install -m 644 /opt/__SLUG__/app/deploy/__SLUG__.cron /etc/cron.d/__SLUG__
+  # On a host the hall shares, its hall-nightly.sh runs the rollup and backup
+  # of every game and checks in with Sentry once for all; a game on a box of
+  # its own schedules its own.
+  if [ -f /etc/cron.d/gamehall ]; then rm -f /etc/cron.d/__SLUG__
+  else install -m 644 /opt/__SLUG__/app/deploy/__SLUG__.cron /etc/cron.d/__SLUG__; fi
   mkdir -p /var/log/__SLUG__
   systemctl daemon-reload
   systemctl enable --now __SLUG__