there's actually a built-in Function which directly does this (as Commands require input from the person playing the game, though there may be a way of calling~invoking a Command too):
http://docs.textadventures.co.uk/quest/functions/corelibrary/showroomdescription.html
in code:
ShowRoomDescription ()
// the () are parenthesis (left and right), not the 'O' letter, nor zero.
or, to do this (the calling of a Function) in the GUI~Editor:
run as script -> add new script -> scripts -> 'call function' Script -> (see below)
Function Name (the small rectangle text box): ShowRoomDescription
Add Parameters (the box box with the 'add' button): (do NOT add any parameters)
// I don't think for the Function Name that you need the parenthesis, but if this doesn't work, then put in the parenthesis, and then it should work.
if you actually wanted to make a Command, and then call upon it... hopefully someone more knowledgeable with quest, can answer, and~or help you with it.
err...
the 'ShowRoomDescription ()' is only for the room that your player is currently within.
if you want for a specific room, which your player is not currently in...
then you just need to do this instead:
in code:
invoke (room_name, "description")
example: invoke (FinalDungeon, "description")
// hopefully invoke works with a pure textual description too, and not only for a scriptive description...
// you can also use 'do' too: http://docs.textadventures.co.uk/quest/scripts/do.html
or, in the GUI~Editor:
not sure how to do it... lol
and for non-room Objects:
invoke (object_name, "look")
example: invoke (Desk, "look")