> ## Documentation Index
> Fetch the complete documentation index at: https://docs.arlet.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Resources

> Official MCP example servers, the registry, and the specification to learn from and build on.

When you build an MCP server, you rarely have to start from a blank file. The Model Context
Protocol project maintains reference implementations, a registry for publishing and
discovering servers, and the specification itself. Lean on these to learn proven patterns and
to ship your server to users.

## Reference Servers

The official [`modelcontextprotocol/servers`](https://github.com/modelcontextprotocol/servers)
repository is a large collection of reference and example MCP servers. It's the best place to
see how real servers structure tools, handle authentication, and format output.

* **Learn by example.** Read a server close to your use case before writing your own.
* **Copy proven patterns.** Tool naming, schema design, and error handling are already
  worked out — port what fits.
* **Use them as test fixtures.** Run an existing server to confirm your client setup works
  before debugging your own.

## MCP Registry

The [MCP Registry](https://github.com/modelcontextprotocol/registry) is a community-driven
registry service for publishing and discovering MCP servers.

* **Discover existing servers** before building something that already exists.
* **Publish your server** so agents and users can find and install it.
* **Reuse metadata conventions** the registry expects (name, description, capabilities) when
  you design your own server's manifest.

## Specification & Documentation

The [`modelcontextprotocol/modelcontextprotocol`](https://github.com/modelcontextprotocol/modelcontextprotocol)
repository holds the official specification and documentation.

* **Use it as the source of truth** for protocol behavior — transports, capabilities,
  versioning, and message formats.
* **Check it when SDKs disagree** or when you hit edge cases that examples don't cover.
* **Track changes** to stay compatible as the protocol evolves.

<Note>
  Building hands-on? Pair these resources with the
  [MCP Server Development Tips](/guides/mcp-server-tips) for practical design guidelines.
</Note>

## Explore

<CardGroup cols={2}>
  <Card title="Reference Servers" icon="server" href="https://github.com/modelcontextprotocol/servers">
    Official example and reference MCP servers
  </Card>

  <Card title="MCP Registry" icon="box-archive" href="https://github.com/modelcontextprotocol/registry">
    Publish and discover MCP servers
  </Card>

  <Card title="Specification" icon="book" href="https://github.com/modelcontextprotocol/modelcontextprotocol">
    The official protocol specification and docs
  </Card>

  <Card title="Development Tips" icon="lightbulb" href="/guides/mcp-server-tips">
    Practical guidelines for building MCP servers
  </Card>
</CardGroup>