The official MCP Registry, tested: how many of its 57,000 servers work

57,000 listed, two thirds served remotely, six in ten of those work

On 6 November the official MCP Registry listed 57,553 servers (the latest version of each). A third only run as a package on your own machine, which we don't test. The other 38,666 are served remotely, at 39,494 distinct addresses. Connecting to each, 23,314 did the handshake and listed their tools: 59%. Another 30% ask for a sign in first; the last tenth are broken, unreachable, or have an address with blanks to fill in.

Most sign ins are OAuth; 512 addresses want payment first

Of the 11,894 addresses asking for a sign in, 8,921 use OAuth the way the MCP spec says (their reply says where to authorize), 2,461 want a key, and 512 answer 402, payment first: on 200 hosts, most likely x402 services that charge by the call. Of Apify's 888 addresses, 874 ask for a sign in.

The broken ones: not found, server errors, lapsed domains

Of the 3,887 addresses that don't work, the most are not found (1,111) and server errors (657). 635 names no longer resolve and 263 fail on their certificate, mostly a domain pointed at a host that has no certificate for it. Since Smithery closed its hosting on 31 October, none of the 217 addresses on it works; the registry still lists them all.

One host lists 2,365 servers, all advertising to agents

The host with the most entries is a Cloudflare Workers address. All 2,365 of its servers work, but their tools are small things, checking the shape of an ABA number or looking up a country code, and each server has one tool whose description tells the agent to "follow start_here.hop first", through a redirect with utm parameters, to the products it promotes. This one sender makes up a tenth of the working servers.

We flag such descriptions: these servers stay out of search results and the words aren't reproduced. Another 110 servers tell the agent to always use them first; sometimes that is the order a server needs, sometimes it is pushing itself ahead of others, so we show the words and let the reader judge. The three biggest hosts make up 23% of the working servers; 15,654 hosts have a single working server each.

A median handshake of 1.6 seconds and 8 tools

At the working addresses the median handshake took 1.6 seconds and the slowest tenth 3.9 or more (measured from one machine of ours: where it sits changes the times). The median server lists 8 tools; 5,624 addresses list more than 30, which takes a lot of an agent's context if all are loaded at once.

A handshake isn't a working call

A handshake and a tool list only show that a server is up and speaks the protocol. We picked 6 servers that need no sign in and called read only tools: 5 worked; a Chinese stock data server let us shake hands and list its tools with no key, then asked for one when a tool was called. So servers that did a real task for us are marked Use tried.

Half the entries arrived in the last five weeks

Of the 57,553 entries, 28,141 were published after 1 October. The registry grows fast, but much of it in bulk: 7,361 servers sit on hosts with 50 or more entries each. By what they are for, code and development leads among the working servers, then maps, weather and travel, search and the web, and finance.