I’m not sure this is targeted correctly. As a general rule, new protocols for the web work best when they are associated with individual URLs, not with the somewhat nebulous concept of a site.
Have you considered something like <script type="text/llm"> or Link: <https://api.example.com/llms/foo>; rel="llm:foo", or just normal content negotiation on individual pages?
Have you considered something like <script type="text/llm"> or Link: <https://api.example.com/llms/foo>; rel="llm:foo", or just normal content negotiation on individual pages?