Monsters and mortals can't enter, unless allowed from someone on the inside
Grey Rocks and Greyer Sea by Charles G. D.
When he wrote This excerpt he was referring to knowledge, he said that he reads a book a day and that knowledge was his banknote that got him so far,
The words in the brackets are telling the actors what to physically do, meaning it would be a stage direction.
It isn't dialogue because that is a conversation between two people.
It isn't dialect because that is how a person speaks. There is no speaking in the brackets.
It isn't narration because it isn't spoken allowed for the audience.
It isn't a description because that is too broad a term more often used for emotions.