diff --git a/scripts/ci/docker-prune.sh b/scripts/ci/docker-prune.sh
index b6b4f4dc..bff35bf6 100644
--- a/scripts/ci/docker-prune.sh
+++ b/scripts/ci/docker-prune.sh
@@ -1,11 +1,11 @@
 #!/usr/bin/env bash
-# CI runner disk hygiene — invoked by docker-prune.service (every 30 min). Lives in a real script
+# CI runner disk hygiene — invoked by docker-prune.service (every 2 min). Lives in a real script
 # rather than inline ExecStart= lines because systemd does its OWN $-expansion on ExecStart and
 # empties shell vars / $(...) before /bin/sh sees them (silently breaking the logic under `|| true`).
 #
-# See docker-prune.service for the full why. The headline: the act_runner cache server's blob store
-# lives INSIDE the long-running runner container's writable layer, where `docker prune` can't reach
-# it — left alone it grows to tens of GB and fills the disk on its own.
+# See docker-prune.service for the full why. Sibling: docker-reclaim.sh (hourly) handles what
+# act_runner *leaks* — per-job volumes, stale networks, old build cache. This one handles what
+# CI legitimately *produces* and then abandons: per-SHA app tags and the layers they pin.
 set -u
 export PATH=/usr/bin:/bin:/usr/local/bin:$PATH
 
@@ -23,11 +23,26 @@ MIN_FREE_GB=${MIN_FREE_GB:-60}          # ...or this little is left, whichever t
                                         # 2026-07-29: zero burst clears fired in six hours
                                         # while deb still died of ENOSPC between polls.
 
-# 1) Routine: trim aged images / build cache / stopped containers. sha-<commit> tags aren't
-#    dangling, so -a is required. until=2h, not 6h: on a busy day every image is younger than six
-#    hours, so the filter matched nothing and a run reclaimed 0B while `docker system df` was
-#    reporting 20+ GB reclaimable. Two hours still protects a re-run of the push being worked on.
-docker image prune     -af --filter until=2h || true
+# 1) Routine: retire aged per-SHA app tags, then sweep what untagging released.
+#    ⚠ NEVER `docker image prune -a` on this tick. `until=` filters on image CREATION time, so a
+#    CI *base* image (built days ago) that merely has no container this instant counts as "aged" —
+#    including one a job JUST PULLED whose container does not exist yet. Measured 2026-08-07:
+#    this tick ran 07:36:09–:29 and a rust job's `docker create` failed at 07:36:29 with
+#    "No such image: …punktfunk-rust-ci:latest" — three sampled failures that morning, each
+#    coinciding with a prune run to the second — and every idle base image was re-pulled within
+#    minutes (4–7 GB each), churning the LAN registry for nothing.
+#    The only tag debris this host actually accretes is the per-SHA app tags (web/docs — their
+#    creation time IS the local build time, so a 2h age gate is exact), and a dangling-only prune
+#    cannot touch a tagged image, so neither step can race a starting job.
+now=$(date +%s)
+docker images --format '{{.Repository}}:{{.Tag}}' 2>/dev/null | grep ':sha-' | while read -r ref; do
+  created=$(docker image inspect -f '{{.Created}}' "$ref" 2>/dev/null) || continue
+  cts=$(date -d "$created" +%s 2>/dev/null) || continue
+  if [ $((now - cts)) -ge 7200 ]; then
+    docker rmi "$ref" >/dev/null 2>&1 || true
+  fi
+done
+docker image prune      -f || true
 docker builder prune   -af --filter until=2h || true
 docker buildx prune    -af --filter until=2h || true
 docker container prune  -f --filter until=2h || true
@@ -44,7 +59,9 @@ docker network prune -f --filter until=2h || true
 #    what matters is absolute headroom for three concurrent target/ dirs, not a ratio — and the
 #    ratio moves whenever the disk is resized (it went 123 G -> 175 G on 2026-07-29) while the
 #    headroom three jobs need does not. In-use images are protected by the daemon, so a burst clear
-#    cannot pull the rug from a live job.
+#    cannot pull the rug from a live job — but the blanket `-a` prune below CAN race an image that
+#    is pulled-but-not-yet-created (the section 1 lesson). That narrow window is accepted HERE
+#    only: when the alternative is every concurrent job dying of ENOSPC, one job re-pulling loses.
 PCT=$(df --output=pcent / | tr -dc '0-9')
 FREE_GB=$(df --output=avail -BG / | tr -dc '0-9')
 # Two flat tests into a flag rather than one multi-line `{ …; } || { …; }` condition: the brace-group
diff --git a/scripts/ci/docker-reclaim.service b/scripts/ci/docker-reclaim.service
new file mode 100644
index 00000000..7e794407
--- /dev/null
+++ b/scripts/ci/docker-reclaim.service
@@ -0,0 +1,20 @@
+# Hourly reclaim of Docker resources act_runner LEAKS (per-job volumes, stale networks, old build
+# cache). Sibling of docker-prune.service, which handles what CI legitimately produces and then
+# abandons; the split matters because this one must stay conservative enough to run while jobs are
+# live (dangling-only volumes, age-gated networks) — see docker-reclaim.sh for the full why.
+#
+# Install: see the header of docker-reclaim.sh (note the installed unit name is
+# ci-docker-reclaim.service — existing fleet hosts already run it under that name).
+
+[Unit]
+Description=Reclaim disk leaked by Gitea act_runner (per-job volumes, networks, stale build cache)
+Documentation=https://git.unom.io/unom/punktfunk
+After=docker.service
+Requires=docker.service
+
+[Service]
+Type=oneshot
+ExecStart=/usr/local/sbin/ci-docker-reclaim.sh
+# Never let maintenance starve a running build.
+Nice=10
+IOSchedulingClass=idle
diff --git a/scripts/ci/docker-reclaim.sh b/scripts/ci/docker-reclaim.sh
new file mode 100644
index 00000000..9b50423f
--- /dev/null
+++ b/scripts/ci/docker-reclaim.sh
@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+# Reclaim the disk that Gitea act_runner leaks on this host.
+#
+# Why this exists: act_runner creates a per-job network and a pair of named volumes, and leaks both
+# when a job is killed or the runner restarts. By 2026-07-25 that had accumulated 252 unused volumes
+# (11.7 GB) and 94 stale networks — some dating to task 5626 while current tasks were ~25233 — and
+# concurrent builds then exhausted the disk, failing CI with "No space left on device" at both the
+# cargo and the Docker/overlayfs layer. The stale networks are also what once broke the docs deploy
+# by exhausting Docker's default address pool and swallowing the DMZ 192.168.50.0/24 range.
+#
+# This ran on home-runner-1 only, hand-installed; home-runner-2 went without it and by 2026-08-07
+# had re-accumulated 176 leaked volumes (~60 GB) + 22 GB build cache and spent two days failing
+# jobs at ENOSPC. Hence checked in: BOTH runner hosts install it, from here.
+#
+# Install on a runner host (root):
+#   install -m755 scripts/ci/docker-reclaim.sh /usr/local/sbin/ci-docker-reclaim.sh
+#   install -m644 scripts/ci/docker-reclaim.service /etc/systemd/system/ci-docker-reclaim.service
+#   install -m644 scripts/ci/docker-reclaim.timer   /etc/systemd/system/ci-docker-reclaim.timer
+#   systemctl daemon-reload && systemctl enable --now ci-docker-reclaim.timer
+#
+# Deliberately NOT `docker volume prune -a`: that would also delete any intentional named volume
+# that merely has no container attached at the moment the timer fires — e.g. the `docker-mirror`
+# pull-through registry cache or the runner cache during a restart — silently destroying it. Only
+# volumes act_runner named are removed here.
+#
+# Also deliberately NOT pruning images: on this host the per-SHA CI tags share all their layers with
+# `:latest`, so removing them reclaims nothing while forcing re-pulls. `docker system df`'s
+# "RECLAIMABLE" column counts shared layers once per image and overstates the win badly.
+# (docker-prune.sh owns tag retirement — age-gated and never `image prune -a`, see its header.)
+set -uo pipefail
+
+log() { echo "ci-docker-reclaim: $*"; }
+
+before_avail=$(df --output=avail -BM / | tail -1 | tr -dc '0-9')
+
+# 1. Leaked per-job volumes — dangling AND named by act_runner. In-use volumes are never listed as
+#    dangling, so a running job's volumes cannot be hit.
+mapfile -t stale_vols < <(docker volume ls -qf dangling=true 2>/dev/null | grep '^GITEA-ACTIONS-TASK-' || true)
+if ((${#stale_vols[@]})); then
+    printf '%s\n' "${stale_vols[@]}" | xargs -r docker volume rm >/dev/null 2>&1
+    log "removed ${#stale_vols[@]} leaked act_runner volumes"
+else
+    log "no leaked act_runner volumes"
+fi
+
+# 2. Unused networks older than 2h — never touches a live job's network (it is in use), and the age
+#    filter keeps a just-created one safe against a race with a starting job.
+net_out=$(docker network prune -f --filter until=2h 2>&1 | grep -c '^GITEA-ACTIONS' || true)
+log "removed ${net_out:-0} stale job networks"
+
+# 3. Build cache older than 48h. Recent cache is what makes builds fast, so it is kept.
+cache_freed=$(docker builder prune -f --filter until=48h 2>&1 | awk '/^Total:/ {print $2}')
+log "build cache freed: ${cache_freed:-0B}"
+
+after_avail=$(df --output=avail -BM / | tail -1 | tr -dc '0-9')
+log "avail ${before_avail}M -> ${after_avail}M (reclaimed $((after_avail - before_avail))M)"
+df -h / | tail -1 | sed 's/^/ci-docker-reclaim: /'
diff --git a/scripts/ci/docker-reclaim.timer b/scripts/ci/docker-reclaim.timer
new file mode 100644
index 00000000..ad4edfab
--- /dev/null
+++ b/scripts/ci/docker-reclaim.timer
@@ -0,0 +1,16 @@
+# Hourly is the right cadence for LEAKS: they only accrue when jobs die abnormally, and the
+# per-tick docker-prune.timer (every 2 min) already carries the burst guard for genuine
+# disk-pressure emergencies. Install: see the header of docker-reclaim.sh.
+
+[Unit]
+Description=Hourly reclaim of act_runner-leaked Docker disk
+
+[Timer]
+OnCalendar=hourly
+# Catch up after a reboot rather than waiting for the next slot.
+Persistent=true
+# Spread it off the hour so it does not collide with scheduled CI.
+RandomizedDelaySec=300
+
+[Install]
+WantedBy=timers.target