Langgraph did not call tools

[Tianxiaode2707]

Hello, I tried the
examples/chat_agent_executor_with_function_calling/base.ipynb

the result is as follows which is not the same as example
{'messages': [HumanMessage(content='what is the weather in sf'),
AIMessage(content="I can't provide real-time weather updates at the moment. Please check a reliable weather website or app for the latest information.", response_metadata={'finish_reason': 'stop', 'model_name': 'gpt-4o'}, id='run-43cba69d-3655-41aa-8e4b-e31ef42f500d-0')]}

However, the tool was not called. Could anybody help? Is it library version problem? Thanks in advance.
langchain 0.2.6
langchain-community 0.2.6
langchain-core 0.2.10
langchain-openai 0.1.13
langchain-text-splitters 0.2.2
langgraph 0.1.4
langsmith 0.1.82

[hinthornw]

Without more information, I'm going to assume this was just the LLM behaving non-deterministically. the LLM isn't required to use tools