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The @youdotcom-oss/langchain package provides three DynamicStructuredTool instances for web search and content extraction, built for LangChain.js agents.

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Setup

Install the package with your preferred package manager: 
npm install @youdotcom-oss/langchain
Set your You.com API key. Get your API key at you.com/platform. 
process.env.YDC_API_KEY = "your-api-key";

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Available tools

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youSearch

Web and news search with advanced filtering (dates, sites, file types). 
import { youSearch } from "@youdotcom-oss/langchain";

const searchTool = youSearch({ apiKey: process.env.YDC_API_KEY });
const result = await searchTool.invoke({ query: "latest AI developments", count: 5 });

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youResearch

Comprehensive answers with cited sources. Supports configurable effort levels: lite, standard, deep, and exhaustive. 
import { youResearch } from "@youdotcom-oss/langchain";

const researchTool = youResearch({ apiKey: process.env.YDC_API_KEY });
const result = await researchTool.invoke({ query: "WebAssembly vs JavaScript performance" });

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youContents

Extract full page content from URLs in markdown or HTML format. 
import { youContents } from "@youdotcom-oss/langchain";

const contentsTool = youContents({ apiKey: process.env.YDC_API_KEY });
const result = await contentsTool.invoke({ urls: ["https://example.com/article"] });

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Use with an agent

import { createAgent, initChatModel } from "langchain";
import { youSearch, youResearch, youContents } from "@youdotcom-oss/langchain";

const model = await initChatModel("claude-haiku-4-5", { temperature: 0 });

const agent = createAgent({
  model,
  tools: [
    youSearch(),
    youResearch(),
    youContents(),
  ],
  systemPrompt: "You are a helpful research assistant. Always cite your sources.",
});

const result = await agent.invoke({
  messages: [{ role: "user", content: "What are the latest developments in AI?" }],
});
For more details, see the You.com LangChain package README.
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