Update agent.py

agent.py

@@ -90,7 +90,7 @@ def simple_graph():
 
     def assistant(state: MessagesState):
         """Assistant node"""
-        return {"messages": [chat_with_tools.invoke(state["messages"])]}
+        return {"messages": [chat_with_tools.invoke([sys_msg] + state["messages"])]}
     
     def retriever(state: MessagesState):
         """Retriever node"""