Update app.py

app.py

@@ -71,7 +71,7 @@ class BasicAgent:
     # ---- Low‑level LLM call
     def _call_llm(self, prompt: str, max_tokens: int = 256) -> str:
         resp = self.llm.chat.completions.create(
-            model="gpt-3.5-turbo",
+            model="gpt-4o-mini",
             messages=[
                 {"role": "system", "content": "You are a careful reasoning assistant."},
                 {"role": "user", "content": prompt},
@@ -135,8 +135,16 @@ class BasicAgent:
         return text.strip()
 
     def _generate_answer(self, state: AgentState) -> AgentState:
-        # Get the last search results
-        search_block = "\n".join(state["history"][-1]["results"])  # last search step
+        # Get the last search results with error handling
+        search_block = "No search results available."
+        try:
+            # Find the last search step in history
+            search_steps = [item for item in state["history"] if item.get("step") == "search"]
+            if search_steps and "results" in search_steps[-1]:
+                search_block = "\n".join(search_steps[-1]["results"])
+        except Exception as e:
+            print(f"Error accessing search results: {e}")
+            search_block = "Error retrieving search results."
         
         prompt = f"""
 You are an expert fact-extractor. Using ONLY the text below, answer the question.