Update README.md

README.md

@@ -31,5 +31,6 @@ Files are uploaded using a cache-safe trick to avoid LFS errors.
 1. Set secrets in Space Settings:
    - `BACKUP_REPO`
    - `HF_TOKEN`
+  Please note: Leaving any of these secret empty will not start the Auto Backup Service.
 2. Launch Space → Access VS Code on port 7860.
 3. Work normally, backups run in the background.