diff --git a/start.sh b/start.sh
index 32cf6a8..60dd82e 100644
--- a/start.sh
+++ b/start.sh
@@ -10,5 +10,12 @@ mkdir -p /app/.storage/cancellation-tokens
 # Change ownership to nextjs user
 chown -R nextjs:nodejs /app/.storage
 
+# Ensure runtime dependencies exist (for prebuilt images)
+if [ ! -d "/app/node_modules/hono" ]; then
+  echo "[startup] Installing runtime dependencies (prebuilt safeguard)..."
+  pnpm install --frozen-lockfile --prod --ignore-scripts=false || pnpm install --prod || true
+  pnpm rebuild bcrypt || true
+fi
+
 # Start the application as nextjs user
 exec su-exec nextjs node server-dist/index.js