Well, I don't usually narrate the result before the die is rolled, so typically, the saving throw determines the fiction. In occasions where we realize there was an error, and the saving throw result should have been different, if it is very close to the event, I'll retcon it. If the saving throw was a couple rounds back, though, I probably let it stand.
I think these two sum up my view. I try not to narrate too much before any rolls are made, but the purpose of the roll is to determine the outcome. If the failed result isn't always obvious, sometimes I'll give an indication of if "you feel your muscles begin to siffen, but it passes quickly."To me...The Saving throw chooses the fiction. It doesn't change the fiction. The Saving throw doesn't revert time unless it is given via time magic or time travelling powers
That's a weird way to narrate it. I would have the character feel the ground give way, and then leap back to safety.A player character is moving down a hallway and fails to perceive a pit trap that suddenly opens up beneath their feet. As GM, you call for a Dex/Reflex/Wands saving throw. The PC succeeds and you say: just before you step on the tile you see a hint of a wide crack, darkness, below and as it gives way you are able to throw yourself backward to avoid falling in.
That seems like a simple example, and it is, but it still changes the fiction based on the result of the roll. Prior to the result of the roll, the PC had failed their check.
Also, weird nitpick, but the default save for AD&D was against "spells," unless they had a specific other save.
Also a weird narration, but I think it could be an interesting way to allow a different save than the typical one. For 5E, I might allow this as a way to use a Strength save instead of the Dexterity one I had planned.As an alternative, imagine the PC is banging there 10 foot pole on the ground in front of them and this is supposed to grant them advantage on the perception roll (or passive perception check, or whatever the mechanism is). They still fail to perceive it but succeed at their saving throw. "The floor suddenly gives way where you thought it was solid, but you are able to wedge your pole between the walls and keep from tumbling into the pit." That wedged pole is a new state that has no origin in the saving throw mechanism, but makes sense in the context of the fiction of what was happening right before the save was called for.
That's... horrifying. That description would make it seem like the save is to survive while remaining horribly disfigured/disabled.A more common but less interesting version of this is when the GM tells you what your horrible fate is, and then lets you make a save. "The dragons breathes on you, melting your bones to slag! Make a saving throw." I see it all the time, and in some cases it is more complex and requires back tracking to make sense of a successful save.