I'm now in a position to quote from the AW rulebook (original version). From pp 12, 109:
The rule for moves is to do it, do it. In order for it to be a move and for the player to roll dice, the character has to do something that counts as that move; and whenever the character does something that counts as a move, it’s the move and the player rolls dice. . . .
“Cool, you’re going aggro?” Legit: “oh! No, no, if he’s really blocking the door, whatever, I’ll go the other way.” Not legit: “well no, I’m just shoving him out of my way, I don’t want to roll for it.” The rule for moves is if you do it, you do it, so make with the dice. . . .
Apocalypse World divvies the conversation up in a strict and pretty traditional way. The players’ job is to say what their characters say and undertake to do, first and exclusively; to say what their characters think, feel and remember, also exclusively; and to answer your questions about their characters’ lives and surroundings. Your job as MC is to say everything else: everything about the world, and what everyone in the whole damned world says and does except the players’ characters.
Pages 110-16 then set out the Principles, and p 116 concludes this by addressing the GM, "Whenever someone turns and looks to you to say something, always say what the principles demand."
Page 116 then goes on to list "your [ie the GM's] moves", and says "Whenever there’s a pause in the conversation and everyone looks to you to say something, choose one of these things and say it."
And page 117 sets out "guidelines for choosing your moves", which build on what has already been said in the principles:
Always choose a move that can follow logically from what’s going on in the game’s fiction. It doesn’t have to be the only one, or the most likely, but it does have to make at least some kind of sense.
Generally, limit yourself to a move that’ll (a) set you up for a future harder move, and (b) give the players’ characters some opportunity to act and react. A start to the action, not its conclusion.
However, when a player’s character hands you the perfect opportunity on a golden plate, make as hard and direct a move as you like. It’s not the meaner the better, although mean is often good. Best is: make it irrevocable.
When a player’s character makes a move and the player misses the roll, that’s the cleanest and clearest example there is of an opportunity on a plate. When you’ve been setting something up and it comes together without interference, that counts as an opportunity on a plate too.
But again, unless a player’s character has handed you the opportunity, limit yourself to a move that sets up future moves, your own and the players’ characters’.
<snip>
as per pp 197-98 of the rulebook, "Asking someone straight to do something isn’t trying to seduce or manipulate them. . . . Absent leverage, they’re just talking, and you should have your NPCs agree or accede, decline or refuse, according to their own self-interests."