graph.py

import asyncio
from typing import TypedDict, Annotated
from langchain_openai import ChatOpenAI
from langgraph.prebuilt import ToolNode
from langgraph.graph import StateGraph, END
from langgraph.graph.message import add_messages
from langchain_core.messages import HumanMessage
from langchain.schema.runnable import RunnableLambda

# tools
from langchain_core.tools import tool
from langchain_community.tools.tavily_search import TavilySearchResults
from langchain_community.tools.arxiv.tool import ArxivQueryRun
from langchain_community.tools.openweathermap.tool import OpenWeatherMapQueryRun

@tool
def multiply(first_int: int, second_int: int) -> int:
  """Multiply two integers together."""
  return first_int * second_int

tavily_search = TavilySearchResults(max_results=5)
weather_query = OpenWeatherMapQueryRun()
arxiv_query = ArxivQueryRun()

tool_belt = [
  tavily_search,
  weather_query,
  arxiv_query,
  multiply,
]

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

class AgentState(TypedDict):
  messages: Annotated[list, add_messages]
  loop_count: int

async def call_model(state):
  messages = state["messages"]
  response = llm.invoke(messages)
  return {"messages" : [response]}

def should_continue(state):
  last_message = state["messages"][-1]
  if last_message.tool_calls:
    return "action"
  return END

tool_node = ToolNode(tool_belt)

graph = StateGraph(AgentState)
graph.add_node("agent", call_model)
graph.add_node("action", tool_node)

graph.set_entry_point("agent")
graph.add_conditional_edges(
  "agent",
  should_continue
)
graph.add_edge("action", "agent")

tool_call_graph = graph.compile()

async def main():
  inputs = {"messages" : [HumanMessage(content="Search Arxiv for the QLoRA paper, then search each of the authors to find out their latest Tweet using Tavily! and solve 5 x 5 please.")]}

  async for chunk in tool_call_graph.astream(inputs, stream_mode="updates"):
    for node, values in chunk.items():
      # print(f"Receiving update from node: '{node}'")
      # if node == "action":
      #   print(f"Tool Used: {values['messages'][0].name}")
      print(values["messages"])
      print('\n')


asyncio.run(main())