Which AI agent standards are actually adopted on the web?

These figures come from a weekly agent-readiness scan of the top web domains, so the as-of stamp on this page is a data week, not a single day. A value that ticks up between Monday and Thursday is the same weekly measurement re-read; treating it as a daily series over-reads noise that is not there. Month-over-month change compares this week's scan against the scan from roughly a month earlier — the honest grain for a signal that moves slowly.

Each check has a different meaningful denominator, so ranking standards by their bare share across all domains is a category error. x402 is a payment header for paid content and APIs — it only belongs on the small slice of sites that actually sell access — so its share against every crawled domain understates its penetration of the sites where it would ever appear. AP2, MPP and ACP are similarly niche. A crawl-control file that belongs on every website and a payment endpoint meant for a few thousand commerce sites are not on the same axis. The counts below are raw domain matches; the shares are shown for scale, never for cross-standard ranking.

UCP's count sits an order of magnitude above every other agent standard, and that gap is most likely a detection artifact rather than real adoption. The scan's UCP check reads as a loose heuristic that over-matches domains which do not actually implement the Universal Commerce Protocol. Treat the UCP row as a suspected over-count, and weight the smaller, stricter checks — MCP server cards, A2A agent cards, x402 — more heavily when reading genuine adoption.