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Agentic standards, measured

Most writing about these standards explains what they are. These pages count how many sites actually implement them, and separate the sites that carry the code from the sites where it works. Every figure is dated and carries the population it was measured against.

WebMCP
WebMCP lets a page register tools an agent can call, in the page itself, rather than at a separate endpoint. The site declares what can be done and the agent calls it directly — the page becomes the API.
541 of 606
31 Aug 2026
Markdown negotiation
A site that answers Accept: text/markdown with actual markdown hands an agent the content without the navigation, scripts and layout it would otherwise have to strip. The same URL, a cleaner representation.
9,178 of 57,273
as of 4 Nov 2026
Model Context Protocol
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.
48,822 of 49,613
as of 4 Nov 2026
llms.txt
A file at /llms.txt listing the pages a site considers worth reading, in markdown, as a curated entry point rather than a crawl.
53,531 of 57,273
as of 4 Nov 2026
API catalog
A machine-readable catalogue of a site's APIs at a well-known location, so an agent can find the interface without reading the documentation. Usually an OpenAPI document, discovered through /.well-known/api-catalog.
6,656 of 57,273
as of 4 Nov 2026
UCP (Universal Commerce Protocol)
42,575 websites publish a commerce profile an agent can read.
42,575 sites
28 Sep 2026
ARD (Agentic Resource Discovery)
355 websites tell agents what resources they expose.
355 sites
28 Sep 2026
x402
52 websites publish a price an agent can pay.
52 sites
28 Sep 2026

Observed

Link headers
Capability and relation links delivered in the HTTP response header rather than the document body. We serve them.
no count
Web Bot Auth
Signed HTTP requests that let a site verify which bot is calling it. We do not serve it.
no count
ACP · MPP · AP2
Commerce protocols for agent-initiated purchase and payment. We do not serve them.
no count
DNS-AID
Agent discovery at the DNS layer, published as records rather than over HTTP. We do not serve it.
no count

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