Registry by Modelcontextprotocol is an MCP server tool built with Go, functioning as the official centralized metadata repository for publicly accessible MCP servers. It distributes via container images, while its mcp-publisher CLI tool is a Go binary. Registry connects to underlying package registries and integrates with GitHub and DNS for server location and verification. It provides server discovery for AI clients and supports publishing new server metadata. The service is crucial for the Model Context Protocol ecosystem, enabling dynamic tool invocation.

What does Registry connect to?

The Registry acts as a centralized metadata repository, connecting to underlying package registries such as npm, PyPI, and Docker Hub to provide location data for server code. It integrates with GitHub for authentication and namespace verification, and also uses DNS for domain-based namespace verification. The service itself does not host server code or binaries, instead pointing to their actual locations. This design allows it to serve as a discovery layer over existing distribution channels.

Core features and tools

The Registry exposes a REST API with core endpoints including GET /v0/servers for listing servers, GET /v0/servers/{id} for specific server details, and POST /v0/publish for publishing new servers. A newer API version adds GET /v0.1/servers and specific version queries. A command-line interface tool, mcp-publisher, is also provided. This CLI includes the command "mcp-publisher init" to generate a server.json template, aiding developers in preparing server metadata for publishing.

Who is it for?

The Registry primarily serves server creators publishing MCP servers, MCP clients and aggregators like AI agents and LLMs seeking server discovery, and enterprises managing internal server registries. It supports dynamic tool invocation without hardcoding endpoints for AI clients. Organizations can build custom sub-registries or aggregators using its API. Skip this if you only need to consume server code directly without metadata discovery.

How to get started

Access is granted through a standard OAuth authorization flow for GitHub, or DNS/HTTP verification for domain-based authentication. The official Modelcontextprotocol.io registry currently uses a custom JWT-based authentication system for publishing.

Use cases

• Server Publishing: Developers publish metadata about their MCP servers, including identity, package location, and runtime instructions, making them discoverable by clients.
• Server Discovery: AI clients and aggregators query the registry's API to find available MCP servers and their capabilities, enabling dynamic tool invocation.
• Sub-registry and Aggregator Creation: Organizations and communities build custom sub-registries or aggregators on top of the official registry's API, adding features like curation or enterprise-specific governance.

Registry provides a central hub for MCP server metadata, enabling discovery and publishing across diverse platforms. Its API and CLI tool support developers and AI clients in managing and finding servers. The system connects to existing package registries and authentication services. This makes it a foundational component for the Model Context Protocol ecosystem. Try querying the GET /v0/servers endpoint to explore available MCP servers.