fixed the message format issue

app.py

@@ -570,15 +570,21 @@ async def stream_agent_response(question: str, chat_history: List) -> List[Dict]
             assistant_message["content"] = f"## ❌ Error\n\n{error_msg}"
         
         # Return the message in the correct format for Gradio Chatbot
-        # Format: [(user_message, assistant_message), ...]
-        # Ensure we're returning a list of tuples where each tuple is (user_msg, bot_msg)
+        # Format: list of tuples where each tuple is (user_msg, bot_msg)
+        # For a single response, we return [(None, message)]
+        message_content = ""
+        
         if isinstance(assistant_message, dict) and "content" in assistant_message:
-            return [(None, assistant_message["content"])]
+            message_content = assistant_message["content"]
         elif isinstance(assistant_message, str):
-            return [(None, assistant_message)]
+            message_content = assistant_message
         else:
-            # Fallback: convert to string representation
-            return [(None, str(assistant_message))]
+            message_content = str(assistant_message)
+            
+        # Ensure we return a list of tuples in the format Gradio expects
+        # Each message should be a tuple of (user_msg, bot_msg)
+        # For assistant messages, user_msg is None
+        return [(None, message_content)]
         
     except Exception as e:
         error_msg = f"## ❌ Error\n\nOcurrió un error al procesar tu solicitud:\n\n```\n{str(e)}\n```"