Update app.py

app.py

@@ -600,7 +600,7 @@ class BasicAgent:
                 "vector_store": self.vector_store
             },
             "reasoning": "",
-            "iterations": 0, # Initialize iterations to 0
+            "iterations": 0,
             "history": [HumanMessage(content=question)],
             "final_answer": None,
             "current_task": "Understand the question and plan the next step.",
@@ -609,7 +609,8 @@ class BasicAgent:
         }
 
         try:
-            final_state = self.workflow.invoke(state, {"recursion_limit": 20}) # Increased recursion limit for LangGraph
+            # The invoke method returns an iterator, so we need to consume it to get the final state
+            final_state = self.workflow.invoke(state, {"recursion_limit": 20})
 
             if final_state.get("final_answer") is not None:
                 answer = final_state["final_answer"]
@@ -617,18 +618,26 @@ class BasicAgent:
                 return answer
             else:
                 print(f"--- ERROR: Agent finished without setting 'final_answer' for question: {question} ---")
-                if final_state["history"]:
-                    last_message = final_state["history"][-1].content
+                # --- FIX START ---
+                # Safely get the history from the final_state.
+                # If 'history' key is missing or its value is None, default to an empty list.
+                current_history = final_state.get("history", [])
+                
+                if current_history: # This checks if the list is not empty
+                    last_message = current_history[-1].content
                     print(f"Last message in history: {last_message}")
                     return f"Agent could not fully answer. Last message: {last_message}"
                 else:
                     return "Agent finished without providing a final answer and no history messages."
+                # --- FIX END ---
         except Exception as e:
             print(f"--- FATAL ERROR during agent execution: {e} ---")
+            # In case of an unexpected error, return a helpful message
             return f"An unexpected error occurred during agent execution: {str(e)}"
 
 
 
+
 def run_and_submit_all( profile: gr.OAuthProfile | None):
     """
     Fetches all questions, runs the BasicAgent on them, submits all answers,