npm-registry-mcp-server

A Model Context Protocol (MCP) server that looks up package metadata from the npm registry, powered by package-json by Sindre Sorhus.

• Transport: stdio

• Validation: zod input/output schemas on every tool

• Monitoring: Sentry (@sentry/node) initialized before the server starts, with automatic MCP instrumentation via wrapMcpServerWithSentry

• Runtime: Node.js >= 18 (matches the package-json engines requirement)

Repository: https://github.com/yuchen814/npm-registry-mcp-server

Tools

get_package_metadata

Fetch metadata for a package from the npm registry.

Package-not-found and version-not-found conditions are reported as tool errors with clear messages (PackageNotFoundError / VersionNotFoundError from package-json).

get_package_versions

List every published version and all dist-tags of a package.

Returns { name, distTags, versions, total } as structured content.

Related MCP server: mcp-server-npm

Install & run

npm install
npm run build
npm start          # runs node dist/server.js on stdio

Development (no build step):

npm run dev        # tsx server.ts

Try it with the MCP Inspector:

npm run inspector

Client configuration

Example entry for an MCP client such as Claude Desktop (claude_desktop_config.json):

{
	"mcpServers": {
		"npm-registry": {
			"command": "node",
			"args": ["/absolute/path/to/npm-registry-mcp-server/dist/server.js"],
			"env": {
				"SENTRY_DSN": "https://examplePublicKey@o0.ingest.sentry.io/0"
			}
		}
	}
}

Environment variables

Copy .env.example to get started. Registry selection (including private registries and auth) follows your .npmrc, exactly like npm itself, courtesy of package-json.

Error monitoring

Sentry.init() runs before the MCP server is constructed or connected. Expected lookup failures (unknown package/version) are returned to the client as tool errors and are not sent to Sentry; unexpected failures are captured and flushed before the tool responds. Fatal startup errors are also captured.

License

MIT