Update app.py

app.py

@@ -68,7 +68,8 @@ def openai_call(prompt: str, messages: list = None, model: str = "o3-mini",
     General LLM call to the OpenAI API using the specified model.
     If the message content exceeds MAX_MESSAGE_LENGTH, it is trimmed.
     """
-    if messages is None:
+    # If messages is None or empty, create a default message using the prompt.
+    if messages is None or len(messages) == 0:
         messages = [{"role": "user", "content": prompt}]
     if len(messages[0]['content']) > MAX_MESSAGE_LENGTH:
         messages[0]['content'] = messages[0]['content'][:MAX_MESSAGE_LENGTH]