DOC: <Please write a comprehensive title after the 'DOC: ' prefix>How can I add custom tools using BaseModel and BaseTool to the official sample code?

[guapia233]

Issue with current documentation:

official sample code link:https://github.com/langchain-ai/langgraph/blob/main/examples/multi_agent/hierarchical_agent_teams.ipynb

Idea or request for content:

The custom tool is as follows (the image is highlighted in red because I removed some parts of the function for screenshots, so please ignore it) :

Define the agent node in langgraph as follows (wrong feeling):

The error is as follows:
TypeError: Object of type 'ModelMetaclass' is not JSON serializable
or
TypeError: _run() missing 2 required positional arguments: 'self' and 'network_segment'

[gbaian10]

from dotenv import load_dotenv
from langchain_core.tools import BaseTool
from langchain_openai import ChatOpenAI
from langgraph.prebuilt import create_react_agent
from pydantic import BaseModel, Field


class NmapInput(BaseModel):
    network_segment: str = Field(description="the target's IP address segment")


class Nmap(BaseTool):
    name = "nmap"
    description = "useful for when you need to determine the target's IP address based on a network segment"
    args_schema = NmapInput

    def _run(self, network_segment: str) -> str:
        print(f"{network_segment = }")
        return f"Scanning {network_segment}..."


load_dotenv()
llm = ChatOpenAI(model="gpt-4o-mini")
scan_agent = create_react_agent(llm, tools=[Nmap()])
outputs = scan_agent.invoke({"messages": [("human", "I want to find 127.0.0.1")]})
print(outputs["messages"][-1].content)

[guapia233]

Thanks for the reply, but there seems to be an error

[francisco-pjbank]

You are missing type hints declaring class Nmap

class Nmap(BaseTool):
     name :str = "nmap"
     description :str = "useful for when you need to determine the target's IP address based on a network segment"
     args_schema :Type[BaseModel] = NmapInput

[guapia233]

@francisco-pjbank you are right! I've dealt with it before but thank you~