Update retriever.py

retriever.py

@@ -42,10 +42,10 @@ def retriever(prompt, history):
       Search results in natural language.
   """
   context = "\n\n".join(documents)
-  super_prompt = f"{context}\n\nRetrieve information:\n\nQuestion: {prompt}"
+  super_prompt = f"{context}\n\nRetrieve information:\n\nQuestion: {prompt}. DO NOT precede your response with 'Answer:'. Just give the answer."
 
   response = client.models.generate_content(
-    model="gemini-2.0-flash",
+    model="gemini-2.5-flash",
     contents=super_prompt)
 
   stream_text = ""