Any WebMCP experts out there?

I'm trying to get agents to reliably auto-detect the presence of WebMCP support in my app, but they generally don't notice or use it unless I specifically mention it in my user prompt like "... and use WebMCP pretty please."

I've added content to the page, adding a console.log message, screen reader notes, and of course populating the document.modelContext object, but those aren't doing the trick.

Any ideas?

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This might help (in the Cloudflare Browser Run case, at least):

WebMCP requires Chrome beta features. We have an experimental pool with browser instances running Chrome beta so you can test emerging browser features before they reach stable Chrome. To start a WebMCP session, add lab=true to your /devtools/browser request.

https://developers.cloudflare.com/changelog/post/2026-04-15-br-webmcp/