I don’t think this is about advertising an MCP at all. All of this can be accomplished with plain old HTTP requests. I want to be able to tell users “tell your LLM do go to https://example.com/only-bots”.
There’s absolutely no need for an MCP, because the website will tell the LLM everything it needs to know, including other actions and endpoints available.
It seems like it might be something of what you are looking for, since it leverages HTML to tell agents about website functionality.
One issue I see with WebMCP is that agents basically free-ride on user identity and authentication, which is problematic in some scenarios.