Ref Tools
Helping coding agents never make mistakes working with public or private libraries without wasting the context window.
What is Ref Tools?
Ref Tools is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to helping coding agents never make mistakes working with public or private libraries without wasting the context window.
Helping coding agents never make mistakes working with public or private libraries without wasting the context window.
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
Manual Installation
npx ref-toolsConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use Ref Tools
Ref Tools MCP Server is a documentation intelligence layer for coding agents that surfaces precise, token-efficient answers from both public and private library documentation. By exposing the ref_search_documentation and ref_read_url tools, it enables AI assistants to look up real API references, code examples, and configuration options without pasting entire documentation sites into the context window. Developers use it to reduce hallucinations when Claude generates code that depends on third-party libraries, ensuring the AI works with accurate, up-to-date information.
Prerequisites
- A Ref API key from https://ref.tools (free signup available)
- Node.js 18+ for the npx stdio transport, or an MCP client that supports HTTP transport
- An MCP client such as Claude Desktop, Claude Code, or Cursor
Create a Ref account and get your API key
Go to https://ref.tools, sign up for a free account, and copy your API key from the dashboard. The key is required for all requests.
Configure the HTTP transport (recommended)
Add Ref Tools to your MCP client configuration using the hosted HTTP endpoint. No local installation is required — your API key is passed as a query parameter.
{
"mcpServers": {
"ref-tools": {
"type": "http",
"url": "https://api.ref.tools/mcp?apiKey=YOUR_API_KEY"
}
}
}Or use the npx stdio transport
If your MCP client only supports stdio, you can run the server locally using npx. The REF_API_KEY environment variable authenticates requests.
{
"mcpServers": {
"ref-tools": {
"command": "npx",
"args": ["ref-tools-mcp@latest"],
"env": {
"REF_API_KEY": "your_api_key_here"
}
}
}
}Restart your MCP client
Restart Claude Desktop or your chosen MCP client. The ref_search_documentation and ref_read_url tools should now appear in the available tool list.
Test with a documentation query
Ask Claude to search for documentation on a library you are using in your project. Ref performs semantic search and returns the most relevant excerpt, deduplicated across the session.
Ref Tools Examples
Client configuration
stdio transport configuration using npx for Ref Tools MCP Server.
{
"mcpServers": {
"ref-tools": {
"command": "npx",
"args": ["ref-tools-mcp@latest"],
"env": {
"REF_API_KEY": "your_ref_api_key"
}
}
}
}Prompts to try
Prompts that use ref_search_documentation and ref_read_url to ground code generation in real library documentation.
- "Look up how to configure connection pooling in SQLAlchemy 2.0"
- "What arguments does the Next.js Link component accept?"
- "Find the Zod documentation for discriminated union schemas"
- "How do I set up streaming responses with the Anthropic Python SDK?"
- "Fetch and summarize the readme at https://github.com/pmndrs/zustand"Troubleshooting Ref Tools
npx command fails with module not found error
Ensure Node.js 18+ is installed and npx is available. Run 'npx ref-tools-mcp@latest --version' directly in a terminal to confirm the package installs correctly.
Search results are irrelevant or outdated
Ref's index covers most popular public packages but may lag on very new releases. For the latest docs, use ref_read_url with the direct documentation URL to fetch and convert the current page.
Private documentation is not being found
Private resource indexing must be configured in your Ref dashboard. Connect your private GitHub repos, internal wikis, or custom documentation sites through the account settings before they will appear in search results.
Frequently Asked Questions about Ref Tools
What is Ref Tools?
Ref Tools is a Model Context Protocol (MCP) server that helping coding agents never make mistakes working with public or private libraries without wasting the context window. It connects AI assistants to external tools and data sources through a standardized interface.
How do I install Ref Tools?
Follow the installation instructions on the Ref Tools GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.
Which AI clients work with Ref Tools?
Ref Tools works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is Ref Tools free to use?
Yes, Ref Tools is open source and available under the MIT license. You can use it freely in both personal and commercial projects.
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Set Up Ref Tools in Your Editor
Choose your AI client for step-by-step setup instructions.
Quick Config Preview
Add this to your claude_desktop_config.json or .cursor/mcp.json
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