diff --git a/scripts/ci/one_migration_per_pr.sh b/scripts/ci/one_migration_per_pr.sh
index a40ce8c2..c56e2fdf 100755
--- a/scripts/ci/one_migration_per_pr.sh
+++ b/scripts/ci/one_migration_per_pr.sh
@@ -18,7 +18,12 @@ if [ -z "$BASE_SHA" ] || [ -z "$HEAD_SHA" ]; then
 fi
 
 # Ensure base is present in shallow clones.
+# NOTE: fetch may fail due to fetch-depth/ref settings; validate the commit exists after fetch.
 git fetch --no-tags --depth=1 origin "$BASE_SHA" || true
+if ! git cat-file -e "${BASE_SHA}^{commit}" 2>/dev/null; then
+  echo "Base commit '$BASE_SHA' not found locally even after fetch. Check checkout fetch-depth / ref configuration."
+  exit 2
+fi
 
 # Only count *newly added* migration files. Modified/deleted migrations should not trip this gate.
 # See review thread: https://github.com/abhi1693/openclaw-mission-control/pull/136#discussion_r2807812935
@@ -28,7 +33,9 @@ if [ -z "$ADDED_FILES" ]; then
   exit 0
 fi
 
-MIGRATIONS=$(echo "$ADDED_FILES" | grep -E '^backend/migrations/versions/.*\.py$' || true)
+# Be slightly strict: avoid counting non-migration python files (e.g. __init__.py).
+# Alembic versions typically look like: <hex_revision>_<slug>.py
+MIGRATIONS=$(echo "$ADDED_FILES" | grep -E '^backend/migrations/versions/[0-9a-f]+_.*\.py$' || true)
 COUNT=$(echo "$MIGRATIONS" | sed '/^$/d' | wc -l | tr -d ' ')
 
 if [ "$COUNT" -le 1 ]; then