LangChain v1 완벽 가이드: 에이전트부터 구조화된 출력까지

uv init
uv venv
.venv\Scripts\activate
uv add langchain langchain-openai langchain-community python-dotenv

from langchain.agents import create_agent

agent = create_agent(
    model="gpt-4o-mini",
    tools=[get_weather],
    system_prompt="You are a helpful assistant."
)

response = agent.invoke({"messages": [{"role": "user", "content": "What is the weather in New York?"}]})

from pydantic import BaseModel, Field

class Movie(BaseModel):
    title: str = Field(description="The title of the movie")
    year: int = Field(description="The year the movie was released")

model_with_structure = model.with_structured_output(Movie)
response = model_with_structure.invoke("Provide details about the movie Inception")