try this

app/download_models.py

@@ -4,6 +4,8 @@ from huggingface_hub import hf_hub_download
 # Get the Hugging Face token from environment variable (automatically provided from the secret)
 HUGGINGFACE_TOKEN = os.getenv("key")
 
+if HUGGINGFACE_TOKEN is None:
+    raise ValueError("Hugging Face token is missing. Please set the 'key' environment variable.")
 
 def create_directory(dir_path):
     """