问题描述：

1 Langchain基础

1.1 LangChain 是干什么的？

官方文档说介绍到：

LangChain is the easy way to start building completely custom agents and applications powered by LLMs.^[1]

可以把他理解成是一个调用LLMs的一个高度封装的接口，里面集成了Agent、Function call等等能力，从而极大的简化了大模型开发。

1.2 官方推出的三个不同的工具

[!NOTE] LangChain vs. LangGraph vs. Deep Agents
If you are looking to build an agent, we recommend you start with Deep Agents which comes “batteries-included”, with modern features like automatic compression of long conversations, a virtual filesystem, and subagent-spawning for managing and isolating context.Deep Agents are implementations of LangChain agents. If you don’t need these capabilities or would like to customize your own for your agents and autonomous applications, start with LangChain.

1.2.1 LangChain

上文已表。