LangChainAdapter.mdx

title	LangChainAdapter
description	CopilotKit Adapter for LangChain

{/* GENERATE-DOCS path=packages/runtime/src/service-adapters/langchain/langchain-adapter.ts class=LangChainAdapter */}

Use this adapter to use LangChain as a backend.

return copilotKit.response(
  req,
  new LangChainAdapter({
    chainFn: async ({ messages, tools }) => {
      const model = new ChatOpenAI({ modelName: "gpt-4o" });
      return model.stream(messages, { tools });
    },
  })
);

The async handler function can return:

• a simple string response
• a LangChain stream IterableReadableStream
• a LangChain BaseMessageChunk object
• a LangChain AIMessage object

Constructor

process(request: CopilotRuntimeChatCompletionRequest)