I'll give that a try. Hopefully it reduces the text vomit Claude tends to do.
Right now all I have is
> - Give terse and concise answers unless the user asks you to elaborate. Big walls of text are not usefull when trying to communicate.
Don't bother, no incantation can fix it.
I recently asked Claude (Opus 5) to give me guidance on how to instruct it to be less verbose in a way that it will _actually follow_. Its response was something to the effect of (and I'm heavily paraphrasing here) "'Succinct' and 'short' aren't objective measurements. Try providing a strict word budget instead."
Given that guidance, I tried specifying "Unless I ask you to elaborate, respond with no more than one paragraph, using sentences of 20 words or fewer." It works...ish. I still see it violate this rule regularly, but it's less bad IME.