The Demiplane spell states (emphasis mine):
Each time you cast this spell, you can create a new demiplane, or have the shadowy door connect to a demiplane you created with a previous casting of this spell. Additionally, if you know the Nature and contents of a demiplane created by a casting of this spell by another creature, you can have the shadowy door connect to its demiplane instead.
How exact must your knowledge of the contents of a demiplane be before you can use this clause in the spell to connect to it?
Some examples of scenarios where you may or may not know enough detail:
- You know the demiplane solely contains a particular creature, but you don’t know everything that’s in that creature’s pockets.
- You know the demiplane solely contains a giant pile of gold coins, and roughly how large it is, but don’t know exactly how many coins there are.
- The demiplane contains 20 distinct items, and you know 19 of them.