Sending a TY is polite. I send them to editors who pass but some agents may find them annoying? I think it’s fine to say TY as long as that’s ALL you say. A lot of authors use any form of communication as a shot to keep the convo going and THAT’S what agents don’t have time for.
Literary Agent. Connoisseur of horror, schadenfreude, and caffeine. Founder of @TheTobiasAgency . Opinions are my own. (he/him)