NPMLens MCP

npmlens-mcp lets your coding agent (such as Claude, Cursor, Copilot, Gemini or Codex) search the npm registry and fetch package context (README, downloads, GitHub info, usage snippets). It acts as a Model‑Context‑Protocol (MCP) server, giving your AI assistant a structured way to discover libraries and integrate them quickly.

Changelog | Contributing | Troubleshooting | Tool reference

Key features

• Structured npm search with optional ranking weights.
• Direct README fetch (optionally truncated).
• Enriched package info (downloads + GitHub details).
• Usage snippet extraction from README.
• Stdio MCP transport, ready for MCP‑compatible clients.

Disclaimers

npmlens-mcp performs network requests to npm and GitHub when tools are used. Avoid sharing secrets in prompts; set GITHUB_TOKEN only if you want higher GitHub rate limits.

Requirements

• Node.js v18.17 or newer
• npm (or pnpm)

Getting started

Add the following config to your MCP client:

{
  "mcpServers": {
    "npmlens": {
      "command": "npx",
      "args": ["-y", "npmlens-mcp@latest"]
    }
  }
}

[!NOTE] Using npmlens-mcp@latest ensures your MCP client always runs the latest published version.

MCP Client configuration

amp mcp add npmlens -- npx npmlens-mcp@latest

claude mcp add npmlens npx npmlens-mcp@latest

codex mcp add npmlens -- npx npmlens-mcp@latest

Start Copilot CLI:

copilot

Start the dialog to add a new MCP server by running:

/mcp add

Configure the following fields and press CTRL+S to save:

• Server name: npmlens
• Server Type: Local
• Command: npx -y npmlens-mcp@latest

code --add-mcp '{"name":"npmlens","command":"npx","args":["-y","npmlens-mcp@latest"]}'

Go to Cursor Settings -> MCP -> New MCP Server. Use the config provided above.

Project wide:

gemini mcp add npmlens npx npmlens-mcp@latest

Globally:

gemini mcp add -s user npmlens npx npmlens-mcp@latest

Alternatively, follow the Gemini CLI MCP guide and use the standard config from above.

Go to Settings | Tools | AI Assistant | Model Context Protocol (MCP) -> Add. Use the config provided above. Same for Junie under Settings | Tools | Junie | MCP Settings -> Add.

Go to Settings | AI | Manage MCP Servers -> + Add and use the config provided above.

Your first prompt

Enter one of the following prompts in your MCP client to check if everything works:

Basic search and info:

Find 5 React debounce hook libraries, include weekly downloads, and
fetch the README for the top result.

Compare packages:

Compare react-query, swr, and apollo-client. Show me their weekly
downloads, GitHub stars, and licenses.

Version history:

Show me all TypeScript versions released in the last 6 months with
their publish dates.

Dependencies:

What are the dependencies of express? Include dev dependencies.

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Advanced and Local Usage

Looking for JSON‑RPC examples, tool schemas, the local dev CLI, troubleshooting, or contributor setup?

• See docs/advanced.md for all technical details.
• See CONTRIBUTING.md for contributing guidelines.

Tools

Below are the tools exposed by NPMLens MCP. For full JSON schemas, see the Tool reference.

Core Search & Information

• search_npm

  • Search the npm registry with optional ranking weights.
  • Args: query (string, required), size (1..250), from (offset), weights (object with quality, popularity, maintenance).
  • Returns: { total, results[] } where each result includes name, version, description, links, score, etc.

• search_by_keywords

  • Search npm packages by specific keywords/tags with AND/OR operators.
  • Args: keywords (array of strings, required), operator (AND | OR, default AND), size (1..250).
  • Returns: Same as search_npm.
  • Example: Find packages with "react" AND "hooks" AND "typescript".

• get_readme

  • Fetch README markdown for a package (optionally by version).
  • Args: name (string, required), version (string), truncateAt (number).
  • Returns: JSON metadata (name, version, repository, homepage) and the README as text content.

• get_package_info

  • Enriched package info combining registry metadata, npm downloads, and GitHub details.
  • Args: name (string, required), version (string), includeReadme (boolean).
  • Returns: name, version, repository, homepage, github{ fullName, url, stars, forks, license }, downloadsLastWeek, and optional readme.

• get_usage_snippet

  • Extract a likely usage snippet from a package README.
  • Args: name (string, required), version (string).
  • Returns: { snippet: { language, code, heading } }.

Version & Dependency Analysis

• get_package_versions

  • List all available versions of a package with publish dates and dist tags.
  • Args: name (string, required), limit (number), since (string - ISO date or relative like "6 months").
  • Returns: { name, versions[] } where each version includes version, date, tags[].
  • Example: "Show me all React versions from the last year".

• get_package_dependencies

  • Get the dependency tree for a package.
  • Args: name (string, required), version (string), depth (1-3, default 1), includeDevDependencies (boolean).
  • Returns: { name, version, dependencies[], devDependencies[] } with name and version range for each dependency.
  • Example: "What dependencies does express have?".

Metrics & Comparison

• get_downloads

  • Fetch npm downloads for the last day/week/month.
  • Args: name (string, required), period (day | week | month, default week).
  • Returns: { downloads, start, end, package }.

• compare_packages

  • Compare multiple npm packages side-by-side.
  • Args: packages (array of 1-10 package names, required).
  • Returns: Array of comparison data with name, version, description, downloads, stars, forks, license, repository, homepage, and optional error.
  • Fetches all packages in parallel for performance.
  • Example: "Compare react-query, swr, and apollo-client".

Sample usage queries

Below are example queries you can use with your AI assistant to test all 9 NPMLens tools:

search_npm

Search npm for react testing libraries

Find packages related to "typescript validation" and show me the top 5 results

get_readme

Show me the README for express

Get the README for react version 18.0.0

get_package_info

Get detailed information about the lodash package

Tell me about the vite package including GitHub stats and download numbers

get_downloads

How many downloads does react have in the last week?

Show me download statistics for next for the last month

get_usage_snippet

Show me a usage example for axios

How do I use the commander package? Give me a code snippet.

get_package_versions

List all versions of React from the last year

Show me the version history of TypeScript since 6 months ago

get_package_dependencies

What dependencies does express have?

Show me the dependency tree for next with depth 2

compare_packages

Compare react, vue, and angular

Compare the packages axios, fetch, and node-fetch and help me decide which to use

search_by_keywords

Find packages with keywords "react" AND "hooks" AND "typescript"

Search for packages with keywords "cli" OR "terminal"

Combined queries

You can also ask your AI assistant to use multiple tools together:

Compare react-query, swr, and apollo-client, then show me usage examples for the most popular one

Search for typescript validation libraries, then show me the README and dependencies for the top result

Find the package "zod", show me its download stats, version history, and a usage example

License & Contributing

NPMLens MCP is MIT licensed. Contributions are welcome! Please see CONTRIBUTING.md for guidelines.

Found a bug or have a feature request? Open an issue on GitHub.

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Made with ❤️ for the vibe coding community. Happy coding!