How do I block it from my services? Does it obey robots.txt?
This is a user agent, not a recursive web crawler, so robots.txt explicitly does not apply [0]. As long as I'm not abusing your services you shouldn't care if my instructions to my user agent come in the form of a click of a button, a keyboard shortcut, a script, or an LLM agent.
If it's abusive behavior you are worried about you should be able to detect and block it with rate limits or other tools that target the malicious behavior. If you can't distinguish between my usage and a regular browser then I'm not sure what moral ground you have to claim my usage is hurting you.
[0] "A robot is a program that automatically traverses the Web's hypertext structure by retrieving a document, and recursively retrieving all documents that are referenced." https://www.robotstxt.org/faq/what.html
"That's the neat part, you don't."
If I wanted to use this to do my personal browsing for me, like checking for website updates on those where RSS does not exist, you shouldn't be able to stop me.