Model Context Protocol Servers

What the official reference servers repository is

This is the official repository of reference servers maintained by the protocol steering group, alongside pointers to community-built servers. It is the canonical starting point for learning how servers are written, and it carries an explicit warning about production use that deserves to be read before anything else.

What it does

You clone or install a small set of demonstration servers that show how the protocol exposes tools, resources and prompts, run them through a package runner, and wire the configuration into a client. The loop is install, configure, learn.

The active set covers a test server, web fetching, filesystem access with configurable controls, repository operations, a knowledge-graph memory store, structured reasoning and time conversion. A larger group including cloud, search, database and chat integrations has been moved to an archived repository as vendors took over maintenance, which is worth understanding because it means much of what people remember from tutorials is no longer maintained here. The project is open source, with new contributions under a permissive licence and older code under a different one, and it links to official software development kits in many languages.

Who it is for

It is aimed at developers learning the protocol, building a first server, or looking for a canonical example to copy. Maintainers of existing servers use it as the reference for how the protocol should behave, and it is the right first stop for anyone who wants to understand the model rather than collect integrations.

What to keep in mind

It is free and open source, so there is nothing to buy and also nothing to complain about commercially. The maintainers state plainly that these are educational examples rather than production-ready solutions, and that you must evaluate your own security requirements and threat model. Quote that warning to anyone treating a reference server as a supported product, because the temptation to ship one is real: it works, it is documented, and its limits are described in a file nobody reads.

Check maintenance status before adopting anything listed. Several high-profile integrations have already been archived and handed to vendors, so an entry that looks canonical may be frozen, and a frozen dependency in an agent's toolchain is a security question rather than an inconvenience.

Scope tightly whatever you do run. The filesystem and repository servers touch exactly the material that matters, so constrain their roots, use read-only access where the task allows, and keep them off directories holding credentials or client data.

Confirm the licence per file, since a repository can mix terms across its history, and treat the whole collection as a teaching aid rather than a component library.