langgraph.graph import END, START, StateGraph from langgraph.graph.message import add_messages from langgraph.prebuilt import ToolNode, tools_condition class State(TypedDict): messages: Annotated[list, add_messages] graph_builder = StateGraph(State) graph_builder.add_node("chatbot", chatbot) tool_node = ToolNode(tools=[tool]) graph_builder.add_node("tools", tool_node) graph_builder.add_conditional_edges("chatbot", tools_condition) graph_builder.add_edge("tools", "chatbot") graph_builder.add_edge(START, "chatbot") https://langchain-ai.github.io/langgraph/tutorials/introduction/#part-3-adding-memory-to-the-chatbot