As far I can tell @Ovinomancer is not suggesting that the successful roll would override established fiction. He was suggesting that a GM might establish additional fictional details that correspond with the successful roll.
Whatever the reason for the success, that reason will now have been present from the first time the PCs met the Captain and before. It's retroactive back to whenever the reason would have started all the way up to when the success happens.I don't see the case for retroactive justification anywhere there. Weaving a success into the fiction properly and well isn't that at all, and that's all that was ever on the table, as @Campbell actually pointed out above. Anyway...
Whatever the reason for the success, that reason will now have been present from the first time the PCs met the Captain and before. It's retroactive back to whenever the reason would have started all the way up to when the success happens.
It can lead to issues. I've seen it. Due to time constraints I have to improv a lot when I DM. When you come up with a reason that suddenly dates back to when the PCs first met the NPC and before, it can create a situation where if you had known that reason the first time the PCs encountered that NPC, it would have colored how you portrayed that NPC and how the PCs would have interacted with it.If that's what you mean by retroactive justification then I'm all for it and I think most here are.
I'm going to reiterate that a declared action must be rooted in the fiction and genre appropriate.
Without knowing what the established fiction in your example or what action X is, I can't blanket answer your question. This isn't being coy -- what's grounded in the fiction for a given action is directly related to what's currently going on in the scene and what's already been established.You've said this a few times so let's explore what it actually means.
If I am saying my characters does X how is that action not rooted in the fiction? I'm also not quite sure what a non-genre appropriate PC action looks like. Now I think you mean something more specific or nuanced by that statement but I can't tell what it is.
You've said this a few times so let's explore what it actually means.
If I am saying my characters does X how is that action not rooted in the fiction? I'm also not quite sure what a non-genre appropriate PC action looks like. Now I think you mean something more specific or nuanced by that statement but I can't tell what it is.
Way to dodge the proof that you said you can retroactively justify rolls.
Yes, unless the character was meant to be a villain, in which case violating the accepted norms is genre appropriate for that character. But, yeah, in a game like Pendragon where the premise is that you're playing knights in Arthurian legend, such action declarations are very much genre-inappropriate.A possible example of a non-genre-appropriate behavior could be, in a setting where characters are expected to life by a code of honor (such as Arthurian stuff, Old West) a character who not only declined a duel (or equivalent) but hunted down, ambushed, and killed the person who had challenged him. It might be realistic--especially in the Old West, where there was much less honor than popular fiction would have you believe--but it would violate the expectations of the kind of fiction the TRPG is attempting to emulate.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.