Adoption.
How many of the web's most popular sites register WebMCP tools, as of Sep 21, 2026.
37of the top 10,000 sites use WebMCP.
The top 10,000
What we found on each site. The sites we couldn't read stay in the count.
| Result | Sites | Share |
|---|---|---|
| Use WebMCPRegisters at least one tool | 37 | 0.37% |
| No tools foundLoaded, with no WebMCP tools | 4,368 | 43.7% |
| Blocked usAnswered 401, 403 or 429 | 1,060 | 10.6% |
| Unreachable or not a websiteTimed out, failed, or the name doesn't resolve | 2,696 | 27% |
| SkippedUnsafe, disallowed by robots.txt, redirected away, or a shared app host | 1,842 | 18.4% |
Adoption by popularity
The share of each tier that uses WebMCP, among the sites we could read.
- Top 1,0002.3%9 of 400 readable sites
- Top 10,0000.84%37 of 4,405 readable sites
How sites register tools
Every tool on a listed site, by how the page registers it.
- document.modelContext3,59770.6%
- navigator.modelContext1,33626.2%
- Declarative forms1603.1%
Tools per site
Listed sites by how many tools they register.
How we measure
We start from the Tranco list of the most popular sites. We skip anything on The Block List Project's lists, shared app hosts, and sites whose robots.txt keeps us out. Then we read each homepage and a few of its scripts for signs of WebMCP, and load every site that has them in a real browser, the same check a submitted site gets.
We look at homepages first, so tools that only appear deeper in a site or after sign-in are missed. These numbers undercount adoption.