Assuming you mean I7, when you define a custom direction, it requires a reverse. You can override it in the construction of individual rooms, as you say, but that’s awkward and confusing, and makes your new defined directions kind of useless as a mental construct. Ideally, directions proper in the parser IF or I7 sense should be reserved for things that are sensibly opposites of one another, like fore/aft, up/down, or in/out.