fix error

app.py

@@ -146,7 +146,8 @@ class BasicAgent:
     def __init__(self):
         print("BasicAgent initialized.")
     def __call__(self, question: str) -> str:
-        print(f"Agent received question (first 50 chars): {question[:50]}...")
+        question_text = question.get("question")
+        print(f"Agent received question (first 50 chars): {question_text[:50]}...")
 
         initial_state = {
             "question": question,