Link: /some-page rel="canonical"
Link: /some-page.json rel="alternate" type="application/json"
Link: /some-page.html rel="alternate" type="text/html"
Link: /some-page.md rel="alternate" type="text/markdown"On the flip side, I'd argue that the current centralisation of user agents (in the classical sense here) that benefit from programmatic content negotiation in form of a handful of harnesses like Claude or Codex is a great lever toward forcing the ecosystem to adopt better practices: If Anthropic added content negotiation as described in this thread to Claude, many sites would be incentivised to improve their web servers.
Maybe it will notice those, and maybe it will figure out the pattern for follow-up page requests, but there's no guarantee and it won't help the first request.
I am well aware that few sites are taking that much care of their API in terms of HTTP features, but all of the problems discussed here have solid and battle-tested answers.