debug: trace before and after invoke

main.py

@@ -1136,11 +1136,13 @@ def main():
             
             # Otherwise, treat it as a chat message
             try:
+                print("MAIN: before invoke")
                 result = agent.invoke({"messages": [HumanMessage(content=user_input)]})
+                print(f"MAIN: after invoke, result type={type(result)}")
                 
                 # Extract the AI's response (works for both simple and tool agent)
-                print(f"MAIN: result keys={result.keys()}")
-                if "response" in result:
+                print(f"MAIN: result keys={result.keys() if hasattr(result, 'keys') else 'NO KEYS'}")
+                if result and "response" in result:
                     # OllamaToolAgent returns a separate response field
                     response_text = result["response"]
                 else: