My langgraph program cannot get the tool-calling information from Claude

[tim-chow]

My langgraph program can't get the tool-calling information from Claude. The program is shown below:

from typing import Annotated
from typing_extensions import TypedDict

from langchain_anthropic import ChatAnthropic
from langgraph.graph import StateGraph, START
from langgraph.graph.message import add_messages
from langgraph.prebuilt import ToolNode, tools_condition
from langchain_community.tools.tavily_search import TavilySearchResults


tool = TavilySearchResults(
    max_results=2,
    tavily_api_key="XXX",
)

llm = ChatAnthropic(
    model="claude-3-7-sonnet-20250219",
    base_url="https://XXX",
    api_key="sk-xxx",
)
llm_with_tools = llm.bind_tools([tool])


class State(TypedDict):
    messages: Annotated[list, add_messages]


graph_builder = StateGraph(State)


def chatbot(state: State):
    return {"messages": [llm_with_tools.invoke(state["messages"])]}


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,
)
# Any time a tool is called, we return to the chatbot to decide the next step
graph_builder.add_edge("tools", "chatbot")
graph_builder.add_edge(START, "chatbot")
graph = graph_builder.compile()


def stream_graph_updates(user_input: str):
    for event in graph.stream(
        {"messages": [{"role": "user", "content": user_input}]},
    ):
        for value in event.values():
            for message in value["messages"]:
                print(message.content)
                print(message.tool_calls)


while True:
    try:
        user_input = input("User: ")
        if user_input.lower() in ["quit", "exit", "q"]:
            print("Goodbye!")
            break

        stream_graph_updates(user_input)
    except Exception:  # noqa: BLE001
        # fallback if input() is not available
        user_input = "What do you know about LangGraph?"
        print("User: " + user_input)
        stream_graph_updates(user_input)
        break

When run it, it may output:

User: Please help me search for the weather in Beijing today
I'd be happy to help you search for the current weather in Beijing today. Let me do that for you right away.
[]
User: 

I can't retrieve any information about tool-calling. Are there some usage errors in the program? I would be very grateful if you could help me solve it. Thank you~

[tim-chow]

I found a similar open issue #1153