main.py

from langchain_core.messages import HumanMessage
from langchain_openai import ChatOpenAI
from dotenv import load_dotenv
from langchain.tools import tool
from langgraph.prebuilt import create_react_agent

load_dotenv()
@tool
def addition(a: int, b: int) -> int:
    """Returns the sum of two numbers."""
    return "The sum is: " + str(a + b)

def main():
    model = ChatOpenAI(model="gpt-4o-mini", temperature=0)
    tools = [addition]  # You can add tools later
    # Create the agent
    agent = create_react_agent(model=model, tools=tools)
    print("Hello! I am your chatbot. How can I assist you today?")
    print("Type 'exit' to quit.\n")
    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in ["exit", "quit"]:
            print("Goodbye!")
            break
        print("Bot: ", end="", flush=True)
        # STREAMING RESPONSE (LATEST CORRECT FORMAT)
        for event in agent.stream({"messages": [HumanMessage(content=user_input)]}):
            if "agent" in event:
                msg = event["agent"]["messages"][-1]
                print(msg.content, end="", flush=True)
        print()  # new line after bot response
if __name__ == "__main__":
    main()