Conversation - set scene, answer enquiries, force clues, reveal exit

An extension seems to me like overkill for that. The can't go through undescribed doors rule is already in the Standard Rules. This is all you need:

The oak door is a privately-named undescribed door.
Understand "oak", "door" as the oak door when the oak door is described.

[ some insurance against inference or disambiguation prematurely revealing it ]
Does the player mean doing something to an undescribed thing that is not the player:
it is very unlikely. 

[ replace with some real means of making it described... ]
Instead of thinking, now the oak door is described.