langchainjs

by langchain-ai · AI Agent Frameworks · ★ 18,293

langchainjs is an MCP server by langchain-ai. The agent engineering platform. It has 18,293 GitHub stars and ranks #8 of 609 in AI Agent Frameworks by stars.

Category: AI Agent Frameworks
Author: langchain-ai
GitHub stars: 18,293
This week: +15 stars this week (+0.1%) · +15 forks since 18 Oct 2026
Weekly downloads: 187
Language: TypeScript
License: MIT (open source)
Last update: 2026-10-23 (yesterday)
Links: Source Website npm

How to install langchainjs

langchainjs is published on npm as langchain-mcp-adapters, and it depends on @modelcontextprotocol/sdk. These steps assume it runs as a local stdio server, which is the usual setup.

Check the README. Confirm the start command and note any API keys or environment variables it needs (pass them with -e KEY=value or an env block). You need Node.js for npx.

Add it to Claude Code from a terminal:

claude mcp add langchainjs -- npx -y langchain-mcp-adapters

Or add it to Cursor or Claude Desktop in .cursor/mcp.json or claude_desktop_config.json:

{
  "mcpServers": {
    "langchainjs": {
      "command": "npx",
      "args": [
        "-y",
        "langchain-mcp-adapters"
      ]
    }
  }
}

Restart the client and check it. Run claude mcp list, or open the client's MCP settings, and confirm langchainjs and its tools are listed. The install guide covers VS Code and Codex.

Maintain this project? Get it featured ($99/mo, pinned at the top of AI Agent Frameworks) or see what featuring includes.

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langchainjs compared

Frequently asked questions

What is langchainjs?

langchainjs is an MCP server by langchain-ai in the AI Agent Frameworks category. The agent engineering platform. It has 18,293 GitHub stars and ranks #8 of 609 in AI Agent Frameworks by stars. It is written in TypeScript. It is licensed under MIT. It was last updated yesterday.

Is langchainjs free and open source?

Yes. langchainjs is published under the MIT license, so you can run, modify and self-host it at no cost. If it connects to a paid service, that service's own pricing and API terms still apply. Check the repository for the exact license text before using it commercially.

What are the alternatives to langchainjs?

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Data last updated 25 October 2026. Stars and downloads are refreshed every day from GitHub and npm.