Whose address is this anyway?
We import 18,352 server addresses from the official registry and 4,592 from an aggregator. They are not the same kind of address, and the difference decides whether a server can be measured at all.
When a directory lists an MCP server, it lists a URL. It turns out that URL can mean two very different things, and telling them apart changed our catalogue more than any other single decision.
Two kinds of URL
Some directories publish the address the server actually runs on — the vendor’s own domain. Others publish a proxy address on the directory’s own domain, which forwards to the server after you authenticate with the directory.
official registry 18,352 addresses
aggregator 4,592 addressesA proxy address is fine if you are a customer of that directory. It is useless for measurement: from the outside it answers with an authentication challenge no matter how healthy the server behind it is.
What this changes
Measuring a proxy tells you about the proxy. Uptime, latency and protocol era all belong to the middleman, not the server you care about. A catalogue built mostly from proxy addresses looks busy and says nothing.
How to publish an address
- List the endpoint your server actually serves, on your own domain.
- If you register with an aggregator too, keep the canonical address published somewhere public.
- A stable URL on a domain you control is the single most useful thing you can give a directory.