Tools

@tool
def my_tool(arg1: str, arg2: int) -> str:
    """Tool description here."""
    return f"Result: {arg1} {arg2}"

from langchain_core.tools import BaseTool

from langchain.tools import ToolRuntime

from langchain.tools import InjectedState
from typing import Annotated

def my_tool(state: Annotated[dict, InjectedState]) -> str:
    """Tool that accesses agent state."""
    messages = state["messages"]
    return f"Processed {len(messages)} messages"

from langchain.tools import InjectedStore
from typing import Annotated
from langgraph.store.base import BaseStore

def my_tool(store: Annotated[BaseStore, InjectedStore]) -> str:
    """Tool that accesses the agent store."""
    # Access persistent storage across threads
    data = store.get("namespace", "key")
    return f"Retrieved: {data}"

from langchain_core.tools import InjectedToolArg

from langchain_core.tools import InjectedToolCallId
from typing import Annotated

def my_tool(call_id: Annotated[str, InjectedToolCallId()]) -> str:
    """Tool that accesses its own call ID."""
    return f"Called with ID: {call_id}"

from langchain_core.tools import ToolException

def my_tool(value: int) -> int:
    """Tool that may raise an exception."""
    if value < 0:
        raise ToolException("Value must be non-negative")
    return value * 2