LangChain.js Tools for You.com

Give your LangChain agents real-time access to the web with structured tools. Search current content, research topics with cited sources, and extract live web pages—all through DynamicStructuredTool with full Zod schema validation. Built for LangChain.js, this package brings You.com's search, research, and content extraction directly into your LangChain agents with zero server setup.

Features

Build LangChain agents that can:

• Search the web in real-time - Access current information with advanced filtering (dates, sites, file types)
• Research - Comprehensive answers with cited sources, configurable effort (lite to exhaustive)
• Extract any webpage - Pull full content in markdown or HTML format
• Structured tool inputs - Full Zod schema validation via DynamicStructuredTool
• Zero configuration - Works with any LangChain-compatible model (Anthropic, OpenAI, Google, and more)
• Type-safe - Full TypeScript support with Zod schema validation
• Production-ready - Built on You.com's enterprise search API

AI Agent Skills

For LangChain.js Integration: Use the ydc-langchain-integration skill to quickly integrate You.com tools with your LangChain.js applications.

# Install the LangChain.js integration skill
npx skills add youdotcom-oss/agent-skills --skill ydc-langchain-integration

Once installed, ask your AI agent: "Integrate LangChain.js with You.com tools"

Getting started

Get up and running in 4 quick steps:

1. Get your API key

Visit you.com/platform/api-keys to get your You.com API key. Keep this key secure - you'll need it for configuration.

2. Install the package

Choose your package manager:

# NPM
npm install @youdotcom-oss/langchain langchain

# Bun
bun add @youdotcom-oss/langchain langchain

# Yarn
yarn add @youdotcom-oss/langchain langchain

3. Add tools to your agent

Import the tools and add them to your LangChain agent:

import { getEnvironmentVariable } from '@langchain/core/utils/env';
import { createAgent, initChatModel } from 'langchain';
import * as z from 'zod';
import { youSearch, youResearch, youContents } from '@youdotcom-oss/langchain';

// Fetch the You.com API key as an environment variable
// Get a free API key with credits at https://you.com/platform
const apiKey = getEnvironmentVariable('YDC_API_KEY') ?? '';

// youSearch — web search with titles, URLs, snippets, and news articles
const searchTool = youSearch({ apiKey });

// youResearch — comprehensive answers with cited sources, configurable effort
const researchTool = youResearch({ apiKey });

// youContents — extract full page content from URLs in markdown or HTML
const contentsTool = youContents({ apiKey });

// Create a chat model
const model = await initChatModel('claude-haiku-4-5', {
  temperature: 0,
});

// Define the agent's behavior
const systemPrompt = `You are a helpful research assistant.
Be concise and informative. Always cite your sources.`;

// Structured response format using Zod schema
const responseFormat = z.object({
  summary: z.string().describe('A concise summary of the findings'),
  key_points: z.array(z.string()).describe('Key points from the results'),
  urls: z.array(z.string()).describe('Source URLs'),
});

// Create an agent with all three tools — it picks the right one automatically
const agent = createAgent({
  model,
  tools: [searchTool, researchTool, contentsTool],
  systemPrompt,
  responseFormat,
});

const result = await agent.invoke({
  messages: [{ role: 'user', content: 'What are the latest developments in AI?' }],
});

console.log(result.structuredResponse);

Set your API keys as environment variables:

export YDC_API_KEY=your-api-key-here
export ANTHROPIC_API_KEY=your-anthropic-api-key-here

4. Test your setup

Ask your agent something that needs real-time information:

• "What are the latest developments in quantum computing?"
• "Research the pros and cons of WebAssembly vs JavaScript"
• "Extract and analyze the content from https://anthropic.com"

Your agent will automatically choose the right tool and return up-to-date, accurate answers.

What you can build

Your LangChain agents can now handle requests like these:

Research & information

Current events:

• "What's trending in AI research this week?"
• "Find the latest news about climate policy from the past month"

Technical documentation:

• "Search for TypeScript best practices on the official docs"
• "Find examples of using WebAssembly in production"

Content analysis & extraction

Documentation analysis:

• "Extract and summarize the main points from https://docs.example.com"
• "Get the pricing information from https://competitor.com/pricing"

Multi-page research:

• "Extract content from these 3 blog posts and compare their approaches"
• "Pull the documentation from these URLs and create a summary"

Configuration

The tools work out of the box with environment variables:

export YDC_API_KEY=your-api-key-here

Passing API key directly

You can configure tools individually instead of using environment variables:

import { youSearch } from '@youdotcom-oss/langchain';

const searchTool = youSearch({
  apiKey: 'your-api-key-here', // Override YDC_API_KEY environment variable
});

Configuration type

export type YouToolsConfig = {
  apiKey?: string;  // You.com API key (defaults to YDC_API_KEY env var)
};

Using different model providers

These tools work with any LangChain-compatible model via initChatModel:

import { createAgent, initChatModel } from 'langchain';
import { youSearch } from '@youdotcom-oss/langchain';

// Anthropic Claude
const agent = createAgent({
  model: await initChatModel('claude-haiku-4-5'),
  tools: [youSearch()],
  systemPrompt: 'You are a helpful assistant.',
});

// OpenAI
const agent = createAgent({
  model: await initChatModel('gpt-4'),
  tools: [youSearch()],
  systemPrompt: 'You are a helpful assistant.',
});

Direct tool invocation

You can also invoke tools directly without an agent:

import { youSearch } from '@youdotcom-oss/langchain';

const searchTool = youSearch();
const result = await searchTool.invoke({ query: 'AI news', count: 5 });
console.log(result); // Search results

Available tools

This package provides three tools that your LangChain agents can use automatically:

youSearch()

Comprehensive web and news search with advanced filtering capabilities. Perfect for finding current information, research articles, documentation, and news stories.

When your agent will use this:

• Searching for current information or news
• Finding specific content with filters (dates, sites, file types)
• Research queries requiring multiple results

youResearch()

Research with comprehensive answers and cited sources. Configurable effort levels (lite, standard, deep, exhaustive) let you trade speed for thoroughness.

When your agent will use this:

• Complex questions requiring in-depth analysis
• Research reports needing cited sources
• Thorough comparisons or detailed explanations

youContents()

Extract full page content from URLs in markdown or HTML format. Useful for documentation analysis, content processing, and batch URL extraction.

When your agent will use this:

• Extracting content from specific URLs
• Processing multiple pages in batch
• Analyzing webpage content for further processing

Note: Your LangChain agent automatically selects the right tool based on the user's request. The DynamicStructuredTool provides full Zod schema validation for tool inputs, ensuring type-safe interactions.

Troubleshooting

Problem: "YDC_API_KEY is required" error

Solution: Set your API key as an environment variable:

export YDC_API_KEY=your-api-key-here

Or pass it directly when creating tools:

const searchTool = youSearch({ apiKey: 'your-api-key-here' });

Problem: Agent isn't using the tools

Solution: Make sure you're using createAgent from langchain, which automatically handles tool calling:

import { createAgent, initChatModel } from 'langchain';
import { youSearch } from '@youdotcom-oss/langchain';

const agent = createAgent({
  model: await initChatModel('claude-haiku-4-5'),
  tools: [youSearch()],
  systemPrompt: 'You are a helpful assistant.',
});

Problem: Getting 401 authentication errors

Solution: Verify your API key is correct and properly set:

echo $YDC_API_KEY

Get a new API key at you.com/platform/api-keys if needed.

Problem: Getting rate limit errors (429)

Solution: You've hit the API rate limit. Wait a few minutes before retrying, or check your API usage at you.com/platform/api-keys.

Need more help?

• GitHub Issues: Report bugs
• Email Support: [email protected]

For contributors

Interested in contributing? We'd love your help!

Development setup: See root AGENTS.md for monorepo conventions.

Quick contribution steps:

1. Fork the repository
2. Create a feature branch following CONTRIBUTING.md conventions
3. Follow code style guidelines (Biome enforced)
4. Write tests for your changes
5. Run quality checks: bun run check && bun test
6. Submit a pull request with a clear description

License: MIT - see LICENSE for details

Author: You.com (https://you.com)