I think you mean use "u" instead of ":u" after equipping a tool?
I propose removing ":u" completely. Instead, have "U" function as ":u" currently does and provide an option to 'V'iew inventory [basically the opposite of how "U" currently works]. As far as I remember, an item cannot have an item letter of 'V' in an 80x25 game, so this would be fine.