Update app.py

app.py

@@ -47,7 +47,7 @@ EXPLANATION:
 """
         
         response = client.chat.completions.create(
-            model="gpt-4",
+            model="gpt-5-mini-2025-08-07",
             messages=[
                 {"role": "system", "content": "You are a Qiskit debugging expert."},
                 {"role": "user", "content": prompt}