Update app.py

app.py

@@ -13,7 +13,7 @@ def chat_with_model(user_message, history):
     if history is None:
         history = []
 
-    # Build the full conversation history for the API
+    # prepare messages for the API
     messages = [{"role": "system", "content": "You are a helpful assistant."}]
     for human, bot in history:
         messages.append({"role": "user", "content": human})
@@ -26,27 +26,25 @@ def chat_with_model(user_message, history):
             model="openai/gpt-oss-20b:nebius",
             messages=messages
         )
-        
+
         reply = completion.choices[0].message["content"]
 
-        # Append to history in correct Gradio format (tuple)
+        # MUST be appended as tuple
         history.append((user_message, reply))
-
-        return history, history
+        return history
 
     except Exception as e:
-        error_msg = f"Error: {str(e)}"
-        history.append((user_message, error_msg))
-        return history, history
+        history.append((user_message, f"Error: {str(e)}"))
+        return history
 
 
 with gr.Blocks() as demo:
     gr.Markdown("# 🤖 Chat with HuggingFace Router (OpenAI Compatible)")
-    
+
     chatbot = gr.Chatbot(height=500)
-    text_input = gr.Textbox(label="Type your message")
-    
-    text_input.submit(chat_with_model, [text_input, chatbot], [chatbot, chatbot])
+    text_input = gr.Textbox(label="Your message")
+
+    text_input.submit(chat_with_model, [text_input, chatbot], chatbot)
     text_input.submit(lambda: "", None, text_input)
 
-demo.launch()
+demo.queue(concurrency_count=1, status_update_rate=0).launch()  # still safe