diff --git a/sim/cluster0/scripts/compose-lab-backend.sh b/sim/cluster0/scripts/compose-lab-backend.sh
index 1c2a1a5..3b299d7 100755
--- a/sim/cluster0/scripts/compose-lab-backend.sh
+++ b/sim/cluster0/scripts/compose-lab-backend.sh
@@ -16,6 +16,19 @@ ensure_ac_ms_media_transcode() {
   _mt="${WS}/ac-ms-media-transcode"
   _origin="${AC_MEDIA_TRANSCODE_ORIGIN:-git://f0xx.org/ac/ac-ms-media-transcode}"
   _branch="${AC_GIT_BRANCH:-next}"
+  _seed="${AC_ROOT:-/mnt/repos/ac}/ac-ms-media-transcode"
+  if [ -f "${_mt}/assets/pirate_drift.png" ] && [ -x "${_mt}/bin/run.sh" ]; then
+    log "ac-ms-media-transcode OK at ${_mt}"
+    chmod +x "${_mt}/bin/"*.sh 2>/dev/null || true
+    return 0
+  fi
+  if [ -f "${_seed}/assets/pirate_drift.png" ] && [ -d "${_seed}/.git" ]; then
+    log "seed ac-ms-media-transcode from ${_seed} → ${_mt}"
+    rm -rf "${_mt}"
+    cp -a "${_seed}" "${_mt}"
+    chmod +x "${_mt}/bin/"*.sh 2>/dev/null || true
+    return 0
+  fi
   if [ -d "${_mt}/.git" ]; then
     log "update ac-ms-media-transcode in ${_mt}"
     git -C "${_mt}" fetch origin 2>/dev/null || true
@@ -24,6 +37,7 @@ ensure_ac_ms_media_transcode() {
       || git -C "${_mt}" reset --hard "origin/${_branch}" 2>/dev/null || true
   else
     log "clone ac-ms-media-transcode → ${_mt}"
+    rm -rf "${_mt}"
     git clone --branch "${_branch}" "${_origin}" "${_mt}"
   fi
   chmod +x "${_mt}/bin/"*.sh 2>/dev/null || true