What information should an open mic give you before you apply?

I keep thinking performer listings would save everyone time if the boring stuff was obvious before you put your name down. Set length, whether there’s a bringer, how spots are allocated, roughly when you’ll hear back, and whether it’s actually new-act friendly. What’s the one thing you want to know before applying that nights most often leave vague? I’d rather have a plain accurate listing than three paragraphs telling me the room has a great vibe.