Why do you expect a high level of abuse? Blocking CIDRs of major cloud providers will stop the genuine ChatGPT/Claude traffic. For the other scrapers masquerading as them, just block the agents' user agents.

If you want the LLMs to refuse to scrape your site you could inject lots of encoded trigger words but this would probably affect your SEO score :)

Why would you not put a CDN in front? I’d rather do that than CAPTCHA.