That may work for blocking bad automated crawlers, but an agent acting on behalf of a user wouldn't follow robots.txt. They'd run the risk of hitting the bad URL when trying to understand the page.
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Unfortunately "mass scraping the internet for training data" and an "LLM powered user agent" get lumped together too much as "AI Crawlers". The user agent shouldn't actually be crawling.
They get lumped together because they're more or less indistinguishable and cause similar problems: server load spikes, increased bandwidth, increased AWS bill ... with no discernible benefit for the server operator such as increased user engagement or ad revenue.
Now all automated requests are considered guilty until proven innocent. If you want your agent to be allowed, it's on you to prove that you're different. Maybe start by slowing down your agent so that it doesn't make requests any faster than the average human visitor would.