A cocktail menu is a compressed statement of values before anything gets poured. Every decision in it — what's included, how the drinks are named, how they're described, how long the list runs — tells you something about what the people behind the bar think their job is. Some of what it tells you, you can read before you've ordered anything.
Length is the most informative variable. A short menu is a confidence statement — the bar chose what it was going to be good at and stopped there, which is harder than it sounds and rarer than it should be. A long menu is more often a hedge: against guests who want something specific, against being perceived as limited, against having to take a creative position and commit to it. There are bars with long menus that are long because the program is genuinely deep, but they're rarer than they look. More often, a menu over twenty drinks is fifteen or sixteen of real intention and the rest of coverage.
Watch how it treats the classics. There's a spectrum from "not on the menu, ask your bartender" — which signals the people back there know the canon and don't need to advertise it — to a clearly labeled classics section, which signals respect for the tradition, down through no acknowledgment at all, which is suspicious, to classics listed with proprietary modifications that obscure the original without flagging the change. A bar that won't make a Martini because it's not on the menu is communicating something. A bar that lists a Martini but makes it with house-infused gin and proprietary brine without mentioning this is communicating something different, and arguably worse. What you want from a well-run place is the sense that the bar knows the standard and has chosen its relationship to it deliberately — not avoiding the classics because it can't execute them, and not dressing them up out of embarrassment.
The language is its own tell. Some bars over-describe: exhaustive ingredient lists, flavor notes, origin stories for the base spirit. Some go the other direction — a name, nothing else, figure it out. Both extremes are problems. The over-described menu doesn't trust the drink to carry itself, so it buries the guest in context before the first sip. The stripped-back menu is often performing cool, having decided that needing to know what's in a drink is somehow unsophisticated. The better version is brief and honest: spirit, modifier, what makes this one distinctive. One sentence if the drink genuinely needs it, and nothing that sounds like it was written by someone trying to make gin sound like a lifestyle.
A menu that describes a cocktail as "a meditation on citrus, exploring the tension between bitter and bright" is doing the same thing as a bar that won't make a Martini — prioritizing how the bar presents itself over whether the guest can figure out what they want to drink. The right move, in both cases, is to order something else.