Aironfabio says:
... when to call the moves ...
While PbP can add an extra layer of complication, the rules for when you call for Moves are still pretty much the same as any other play-form. The player posts the fiction of what they are doing (all PbtA games are very much 'fiction first'), and then the GM (with the help of the other players) say if what they described requires a roll, and if so, which Move is being triggered.
This is a discussion, not a ruling, but that can become slow on PbP. Some of this slowness is unavoidable. Best way to avoid slowdowns is to only call for Moves when they are absolutely required to decide the outcome. 'Say yes, or Roll Dice' as the saying goes: First see if you can just let the player have what they want, and only call for dice if 'yes' is not an option (and if 'no' is not the only reasonable answer, but that falls outside the rules).
Depending on the game in question, what they roll or which Move applies, often needs to be a discussion and negotiation between player and GM. GM has 'final say', but that not 'only say'.
In some other games it might make sense for the player to include a roll with the post, this can be problem in PbtA, especially on a Miss. Remember "nothing never happens" so if they roll, something has to happen, and situations that were not meant to be deadly suddenly become so. This can be especially complicated in games that give XP on a Miss, players might be seen as gaming the system and rolling hoping for a Miss (and XP) in the knowledge that nothing serious can happen to them in this safe situation, I don't want to accuse anyone of (deliberately) cheating, but it can be very hard to disentangle these uncalled for rolls and say for sure that they should be ignored.
My 'rule' (though a soft one) is "if the dice come out we are committed". I remember in Apocalypse World, players (often DnD players, given its era) would constantly ask "can I read a situation" and I would point out that that Move says its trigger is "When you
read a charged situation, roll+sharp", so, if they Read a Sitch, the situation
is 'charged' --even if it was not before-- and there is risk. Maybe 'warlord who was friendly gets suspicious "What are you constantly looking around for? Don't you trust us?" they demand'. The dice come out, there will be blood.
While "don't roll till asked to" seems like it might slow things down, if the GM is on the ball, it works out smoother than allowing unsolicited rolls and untangling the outcomes.