create_react_agent without tools

[FahriBilici]

How can I create react agent without tools? When I tried I got this error.

File "/usr/local/lib/python3.11/site-packages/langgraph/prebuilt/tool_node.py", line 111, in __init__
    for tool_ in tools:
TypeError: 'NoneType' object is not iterable

[vbarda]

@FahriBilici why do you need to use a react agent without tools? at that point it's going to be functionally the same as just calling an LLM

[FahriBilici]

Because I build a multi-agent system with a supervised agent structure, one of the agents doesn't require a tool to operate it. In ChatAnthropic, I can give an empty list, which works ok, but in ChatOpenAI It throws an error

[vbarda]

can you just define the agent that doesn't need tools without using create_react_agent? as a simple single-node graph?

[FahriBilici]

How can I do that? Can you give me an example from the documents?

[vbarda]

@FahriBilici you would need to do something like

from langgraph.graph import StateGraph, START
from langgraph.graph.message import MessagesState

def call_model(state: MessagesState):
    # add any logic to customize model system message etc here
    response = model.invoke(state["messages"])
    return {"messages": [response]}
    
builder = StateGraph(MessagesState)
builder.add_node(call_model)
builder.add_edge(START, "call_model")

graph = builder.compile()

[FahriBilici]

Ok, I understand and applied your example, and it also works fine in my case. Thank you for explaining