Ref
A powerful search tool to check technical documentation. Great for finding facts or code snippets. Can be used to search for public documentation on the web or github as well from private resources li
What is Ref?
Ref is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to powerful search tool to check technical documentation. great for finding facts or code snippets. can be used to search for public documentation on the web or github as well from private resources li
A powerful search tool to check technical documentation. Great for finding facts or code snippets. Can be used to search for public documentation on the web or github as well from private resources li
This server falls under the Developer Tools category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- ref_search_documentation
- ref_read_url
Use Cases
Maintainer
Works with
Installation
NPM
npx -y ref-tools-mcpManual Installation
npx -y ref-tools-mcpConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use Ref
Ref is an AI-optimized documentation search MCP server that helps coding agents find precise technical information from public and private libraries without exhausting the context window. It exposes two core tools — ref_search_documentation for semantic documentation search and ref_read_url for fetching and converting web pages to markdown — and filters results to return only the most relevant ~5,000 tokens per query. Teams use it to give Claude accurate, up-to-date library references during code generation, replacing the need to paste entire docs into the context.
Prerequisites
- A Ref API key obtained by signing up at https://ref.tools
- Node.js 18+ installed (for npx/stdio transport) or direct HTTP transport support in your MCP client
- An MCP client such as Claude Desktop, Claude Code, or Cursor
Sign up and obtain an API key
Visit https://ref.tools and create an account to receive your REF_API_KEY. This key authenticates all search and read requests.
Choose your transport method
Ref supports two transports: HTTP (recommended, no local install needed) and stdio via npx. The HTTP transport connects directly to the Ref API endpoint, while stdio runs the npm package locally.
Configure HTTP transport (recommended)
Add the Ref server to your MCP client configuration using the HTTP transport. This requires no local installation — just your API key in the URL.
{
"mcpServers": {
"Ref": {
"type": "http",
"url": "https://api.ref.tools/mcp?apiKey=YOUR_API_KEY"
}
}
}Or configure stdio transport via npx
Alternatively, use the stdio transport which runs the ref-tools-mcp npm package locally. Set REF_API_KEY as an environment variable.
{
"mcpServers": {
"Ref": {
"command": "npx",
"args": ["ref-tools-mcp@latest"],
"env": {
"REF_API_KEY": "your_api_key_here"
}
}
}
}Restart your MCP client and test
Restart Claude Desktop or your client and ask it to search for documentation on a library you use. The ref_search_documentation tool will return focused, deduplicated results.
Ref Examples
Client configuration
HTTP transport configuration for Ref MCP server — the recommended approach that requires no local installation.
{
"mcpServers": {
"Ref": {
"type": "http",
"url": "https://api.ref.tools/mcp?apiKey=YOUR_REF_API_KEY"
}
}
}Prompts to try
Example prompts that use ref_search_documentation and ref_read_url to find precise library information.
- "How do I configure retry logic in the Axios HTTP client?"
- "What are the available options for React Query's useQuery hook?"
- "Show me how to use Pydantic v2's model_validator decorator"
- "What does the --strict flag do in TypeScript compiler options?"
- "Find the FastAPI documentation on dependency injection with Depends"Troubleshooting Ref
401 Unauthorized errors when searching
Verify your REF_API_KEY is correct and active. Log in to ref.tools to check your account status and regenerate the key if necessary.
Search returns no results for a private library
Private resource indexing requires configuration in your Ref account dashboard. Public docs (npm, PyPI, GitHub) are indexed automatically; internal wikis or private repos need manual setup via the Ref web interface.
The ref_read_url tool returns incomplete content
Ref intentionally caps output at ~5,000 tokens to protect context window. If you need more of a page, use ref_search_documentation with a more specific query to retrieve the exact section you need.
Frequently Asked Questions about Ref
What is Ref?
Ref is a Model Context Protocol (MCP) server that powerful search tool to check technical documentation. great for finding facts or code snippets. can be used to search for public documentation on the web or github as well from private resources li It connects AI assistants to external tools and data sources through a standardized interface.
How do I install Ref?
Install via npm with the command: npx -y ref-tools-mcp. Then add the server configuration to your AI client's JSON config file (e.g., claude_desktop_config.json or .cursor/mcp.json).
Which AI clients work with Ref?
Ref works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is Ref free to use?
Yes, Ref is open source and available under the MIT License license. You can use it freely in both personal and commercial projects.
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Quick Config Preview
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