Update app.py

app.py

@@ -2,6 +2,10 @@ import os
 import gradio as gr
 from huggingface_hub import InferenceClient
 
+HF_TOKEN = os.getenv("HF_TOKEN")
+if not HF_TOKEN:
+    raise RuntimeError("HF_TOKEN environment variable not set")
+
 def respond(message, history):
     client = InferenceClient(token=HF_TOKEN, model="Qwen/Qwen3-Next-80B-A3B-Instruct")
     messages = [{"role": "system", "content": "You are a helpful assistant."}]