A lot of discussion of Apocalypse World and similar games (I can't comment on PbtA in general) seems to get confused between describing what one's character does and triggering a player-side move.
The way to describe what one's character does is to describe what one's character does. If that triggers a move, then roll the dice! Otherwise, the GM makes a move - generally a soft move, unless the description of what one's character does hands the GM an opportunity on a plate, in which case they can make as hard and direct a move as they like.
The reason for having a list of player-side moves is to channel the play of the game into the sorts of themes and actions that are central to the game. This is one place where the design quality of a PbtA game is to be found: if the moves are poorly conceived, then play will not naturally push towards player-side moves, and hence to crisis and resolution; rather, it will be apt to wander aimlessly. The lists to be chosen from play the same role: if they're well-designed, they naturally push play towards the sorts of themes and events that the game is aimed towards.
When it comes to custom moves, I've spoken to experienced MCs who can come up with clever stuff very quickly. To me, this seems analogous to learning to GM any other game.
The way to describe what one's character does is to describe what one's character does. If that triggers a move, then roll the dice! Otherwise, the GM makes a move - generally a soft move, unless the description of what one's character does hands the GM an opportunity on a plate, in which case they can make as hard and direct a move as they like.
The reason for having a list of player-side moves is to channel the play of the game into the sorts of themes and actions that are central to the game. This is one place where the design quality of a PbtA game is to be found: if the moves are poorly conceived, then play will not naturally push towards player-side moves, and hence to crisis and resolution; rather, it will be apt to wander aimlessly. The lists to be chosen from play the same role: if they're well-designed, they naturally push play towards the sorts of themes and events that the game is aimed towards.
When it comes to custom moves, I've spoken to experienced MCs who can come up with clever stuff very quickly. To me, this seems analogous to learning to GM any other game.