Who Builds Agents

How to tell if an MCP server is official

An MCP server is official when it was published under the company's own domain and the company points to it from its own site. In the Official MCP Registry, a server named after a reversed domain, such as com.stripe/mcp, can only be published by someone who proved control of stripe.com. A server under io.github.<name> was published by a GitHub account, which may or may not belong to the company.

The one-minute check

  1. Read the name. The part before the slash is the publisher. com.company means the domain company.com was verified. io.github.someone means a GitHub account.
  2. Match the domain. Is that domain the company's real domain, not a lookalike?
  3. Check the company's docs. An official server is documented on the company's own site, and its remote URL is usually on the company's domain.
  4. Check the source. The repository should live in the company's GitHub organization (Stripe's is github.com/stripe/agent-toolkit).

How do I read an MCP server's name?

Registry names are reverse DNS: the part before the slash is a domain written backwards. com.stripe/mcp means stripe.com, and com.example.docs/search rolls up to example.com. A name that starts with io.github. names a GitHub account or organization instead of a domain.

How does the registry check who owns a domain?

Before anyone can publish under a domain namespace, the Official MCP Registry makes them prove control of that domain, with a DNS record or a file served from the domain's website. GitHub namespaces are proven by signing in to that GitHub account. So the namespace tells you who could publish it, not whether the server is any good.

Is a server under io.github always unofficial?

No. Some companies publish from their GitHub organization, for example io.github.<company>. Treat it as official only if the company's own website or docs link to that organization or that server.

What should I check on the company's own site?

Search its developer docs for "MCP" or "Model Context Protocol". An official server is usually documented there, and its remote endpoint is often on the company's domain. Stripe documents its server, and the remote runs at mcp.stripe.com.

Does a listing in an MCP directory make a server official?

No. Directories, this one included, index what is published; they do not make anything official. Provenance comes from the namespace and the company's own site.

How does Who Builds Agents show this?

Every company page here is keyed by the verified domain its servers are published under, so all 17,466 companies are domain owners, never personal accounts. A page shows each server's name, remote and source, whether it answered our weekly live check, and a Verified mark when the company has also claimed its page with an email at that domain. Example: Stripe.

Data from the Official MCP Registry (CC0). Who Builds Agents is not affiliated with it. Related: Which companies ship the most MCP servers?.