LangChain
定义
LangChain 是一个框架 for building LLM applications: chains, agents, tools, and RAG pipelines. It abstracts providers, prompts, and 检索 for quick prototyping and production.
It complements LlamaIndex (which emphasizes 数据和索引); LangChain emphasizes 可组合链和代理循环. 当…时使用 you need RAG, agents with tools, or multi-step prompt workflows with minimal glue code.
工作原理
你组合组件：LLM（OpenAI、Anthropic、本地等）、提示、检索器（vector stores, embeddings), and tools (APIs, search, code). Chains wire them in sequence (例如 prompt → LLM → parser). Agents add a loop: LLM decides which tool to call, you execute it and append the result, repeat until the LLM returns a final answer. LangSmith provides tracing and evaluation. Integrations cover many vector databases, document loaders, and tool APIs. Start with a template (例如 RAG, agent) and swap or add components as needed.
应用场景
LangChain is used to assemble LLM apps quickly: RAG, agents, and workflows with minimal boilerplate.
- Building RAG pipelines and document Q&A applications
- Implementing agents with tools (search, APIs, code)
- Rapid prototyping of LLM workflows with minimal boilerplate