langgraph/examples/docs/quickstart.ipynb

In [1]:

!pip install --quiet -U langchain_openai

[notice] A new release of pip available: 22.3.1 -> 24.0
[notice] To update, run: pip install --upgrade pip

In [2]:

import os
import getpass

os.environ["OPENAI_API_KEY"] = getpass.getpass("OpenAI API Key:")

In [11]:

from typing import List

from langchain_openai import ChatOpenAI
from langchain_core.messages import BaseMessage, HumanMessage
from langgraph.graph import END, MessageGraph

model = ChatOpenAI(temperature=0)

graph = MessageGraph()

def invoke_model(state: List[BaseMessage]):
    return model.invoke(state)

graph.add_node("oracle", invoke_model)
graph.add_edge("oracle", END)

graph.set_entry_point("oracle")

runnable = graph.compile()

In [12]:

runnable.invoke(HumanMessage("What is 1 + 1?"))

Out [12]:

[HumanMessage(content='What is 1 + 1?'), AIMessage(content='1 + 1 equals 2.')]

In [17]:

import json
from langchain_core.messages import ToolMessage
from langchain_core.tools import tool
from langchain_core.utils.function_calling import convert_to_openai_tool

@tool
def multiply(first_number: int, second_number: int):
    """Multiplies two numbers together."""
    return first_number * second_number

model = ChatOpenAI(temperature=0)
model_with_tools = model.bind(tools=[convert_to_openai_tool(multiply)])

graph = MessageGraph()

def invoke_model(state: List[BaseMessage]):
    return model_with_tools.invoke(state)

graph.add_node("oracle", invoke_model)

def invoke_tool(state: List[BaseMessage]):
    tool_calls = state[-1].additional_kwargs.get("tool_calls", [])
    multiply_call = None

    for tool_call in tool_calls:
        if tool_call.get("function").get("name") == "multiply":
            multiply_call = tool_call

    if multiply_call is None:
        raise Exception("No adder input found.")

    res = multiply.invoke(
        json.loads(multiply_call.get("function").get("arguments"))
    )

    return ToolMessage(
        tool_call_id=multiply_call.get("id"),
        content=res
    )

graph.add_node("multiply", invoke_tool)

graph.add_edge("multiply", END)

graph.set_entry_point("oracle")

In [18]:

def router(state: List[BaseMessage]):
    tool_calls = state[-1].additional_kwargs.get("tool_calls", [])
    if len(tool_calls):
        return "multiply"
    else:
        return "end"

graph.add_conditional_edges("oracle", router, {
    "multiply": "multiply",
    "end": END,
})

In [22]:

runnable = graph.compile()

runnable.invoke(HumanMessage("What is 123 * 456?"))

Out [22]:

[HumanMessage(content='What is 123 * 456?'),
 AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_cKnzV4f7sEjnuetuyW8glC7u', 'function': {'arguments': '{"first_number":123,"second_number":456}', 'name': 'multiply'}, 'type': 'function'}]}),
 ToolMessage(content='56088', tool_call_id='call_cKnzV4f7sEjnuetuyW8glC7u')]

In [24]:

runnable.invoke(HumanMessage("What is your name?"))

Out [24]:

[HumanMessage(content='What is your name?'),
 AIMessage(content='My name is Assistant. How can I assist you today?')]

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