Update app.py

app.py

@@ -184,8 +184,11 @@ def submit_message(prompt, prompt_template, temperature, max_tokens, context_len
         state['total_tokens'] += completion['usage']['total_tokens']
     
     except Exception as e:
-        history.append(prompt_msg)
-        history.append("error")
+        history.append(prompt_msg.copy())
+        history.append({
+            "role": "system",
+            "content": f"Error: {e}"
+        }.copy())
 
     total_tokens_used_msg = f"Total tokens used: {state['total_tokens']}"