I have a rule already that triggers last in the every turn rulebook:
The show reports rule is listed last in the every turn rulebook.
But if I list a rule first in the every turn rulebook, it still triggers after the room descriptions. Is there a way I can make a rule trigger every turn, and can print something before the room description?
The room description is displayed by any LOOK action and any successful movement action (which includes a LOOK).
So it sounds like you mean that you want something to happen every turn, before any action results are displayed. You could do that:
Turn sequence rule (this is the boo rule):
The boo rule is listed before the generate action rule in the turn sequence rulebook.
This will display the message before the room description when you move, or before the room description when you LOOK, or before any other action result. (Not before parser errors – those don’t get as far as generating an action.)
But maybe you want something more specific?
Just idle curiosity, but what is the practical difference between right at the end of one turn, and the start of the next?
Emily Short’s Rules Flowchart is old, but these fundamentals haven’t changed. Reductive description of the whole game: follow the Startup rulebook, then follow the Turn Sequence rulebook over and over until you stop, then follow the Shutdown rules.
@OtisTDog lists the Turn Sequence with more annotation here.
Tthere are (at least potentially) things changing at every step; trying to address “difference between right at the end of one turn, and the start of the next” would require knowing exactly what points we’re talking about… (unless you mean the difference between having just finished the final Turn Sequence rule for one turn and having not yet begun the Turn Sequence for the subsequent turn, then it’s easy again: there’s no difference).