Langgraph_sample_Code

from typing import Annotated
from langchain_core.tools import tool
from langchain_openai import ChatOpenAI
from langgraph.graph import StateGraph, START, END
from langgraph.graph.message import add_messages
from langgraph.prebuilt import ToolNode, tools_condition
from typing_extensions import TypedDict
class State(TypedDict):
    messages: Annotated[list, add_messages]
@tool
def add(a: int, b: int) -> int:
    """Add two numbers."""
    return a + b

tools = [add]

llm = ChatOpenAI(
    model="gpt-4o-mini",
    temperature=0
)

llm_with_tools = llm.bind_tools(tools)

def llm_tool(state: State):
    response = llm_with_tools.invoke(state["messages"])

    return {
        "messages": [response]
    }

graph_builder = StateGraph(State)
graph_builder.add_node("llm_tool", llm_tool)
graph_builder.add_node("tools", ToolNode(tools))
graph_builder.add_edge(START, "llm_tool")
graph_builder.add_conditional_edges(
    "llm_tool",
    tools_condition
)
graph_builder.add_edge("tools", "llm_tool")
graph = graph_builder.compile()

result = graph.invoke(
    {
        "messages": [
            {
                "role": "user",
                "content": "What is 2 + 4?"
            }
        ]
    }
)

for msg in result["messages"]:
    print(msg)