MCP adoption: 48,822 sites, November 2026
48,822 of the 49,613 sites we tested implement Model Context Protocol — the index as of November 2026.
49,613 hosts strict-re-graded, of 57,273 listed as of 4 Nov 2026: 57,266 in the full pass of 2 Oct 2026, and 7 probed since
Checks passed across the 48,822 probed hosts: Markdown negotiation 4,751 · Markdown twin at a predictable URL 4,359 · llms.txt 47,896 · API catalog 1,438 · MCP endpoint answers tools/list 48,822.
What these sites let an agent do
The tools most often registered, by how many of the 48,822 register each. Real verbs, read from the page at runtime — enumerated, never called.
997 distinct tool names across 48,822 sites.
How much of this is one plugin
Two instruments read this set and they do not agree, which is the finding rather than a problem. The tool signature — the exact set of names a site registers, treated as a fingerprint — puts 87.5% of the 48,822 in a cluster with at least one other site, and the largest single cluster is 64.6%: one WordPress plugin, registering the same two tools on every site that installs it. The platform column — which fingerprints hosts — attributes just 93.8%, because it does not fingerprint plugins at all. Where the two disagree the signature is the better instrument, and the size of that gap is why we built it.
48,822 pass when we test the behaviour. 791 do not.
Any directory can list sites that claim a standard — the claim is in the source and costs nothing. Separating the two requires testing the behaviour, and dating the result. That is the only thing on this page you cannot get elsewhere.
What Model Context Protocol is
MCP is the protocol an agent uses to discover and call a server's tools. On the open web a site advertises one through a server card, and an agent connects to the endpoint the card names. Read the MCP specification — it is the authority on the design and we are not trying to be.
How we test it
We fetch the server card and then CONNECT to the endpoint it advertises, and count it only where the server answered tools/list — or challenged us for auth, which is an answer.
A server card is a file. It costs nothing to publish and proves nothing about whether anything is listening. The gap between cards published and servers that answer is the single largest gap we measure.
Sites that implement it
64.6% of these are on shopify, 20% of these are on wix, 9.2% of these are on mintlify. The platform supplies the machinery; the domain signals the commitment, and a report says which applies.
All 48,822 of these sites, through the API: every one, in a fixed order, 25 per call, with the total stated.
Model Context Protocol is one signal among several. The rubric says exactly what we look for and how each tier is reached, and a probe can be requested — the probe decides, never the request.
Method and date
Measured 2 Oct 2026. 49,613 hosts strict-re-graded, of 57,273 listed as of 4 Nov 2026: 57,266 in the full pass of 2 Oct 2026, and 7 probed since Every figure on this page carries the population it was measured against; a count without a denominator is not a measurement. How the index is built · All standards.