diff --git a/scripts/run-builder.sh b/scripts/run-builder.sh
index 687b9b6..5cef707 100755
--- a/scripts/run-builder.sh
+++ b/scripts/run-builder.sh
@@ -35,6 +35,24 @@ echo "=== bee builder ==="
 echo "Builder: ${BUILDER_HOST}"
 echo ""
 
+# --- check local repo is in sync with remote ---
+cd "${REPO_ROOT}"
+git fetch --quiet origin main
+LOCAL=$(git rev-parse HEAD)
+REMOTE=$(git rev-parse origin/main)
+if [ "$LOCAL" != "$REMOTE" ]; then
+    echo "ERROR: local repo is not in sync with remote."
+    echo "  local:  $LOCAL"
+    echo "  remote: $REMOTE"
+    echo ""
+    echo "Push or pull before building:"
+    echo "  git push   — if you have unpushed commits"
+    echo "  git pull   — if remote is ahead"
+    exit 1
+fi
+echo "repo: in sync with remote ($LOCAL)"
+echo ""
+
 ssh -o StrictHostKeyChecking=no root@"${BUILDER_HOST}" /bin/sh <<ENDSSH
 set -e
 REPO=/root/bee