As @luke says, it’s not one answer fits all situations: there can be a strong context influence in both what the pre-roll detail is and how it’s narrated afterward.
At one end, there are physically risky things with clear consequences (such as walking along a narrow beam) where it makes sense to say, consequence is that you fall and land badly which from this height would cause an X wound, then if they fail, they mark the wound and pick up the action from them now being on the ground below.
At the other end, there are social interactions where the risks are less clear cut (such as @gyakusetsu and @luke’s thoughts about someone not having your best interests at heart) where the answer is potentially “what is the critical point of interest here?”: is the most interesting thing that the player knows their character is trusting an enemy and so can lean into watching the tragedy? is the most interesting thing that the character doesn’t know whether their plan is helping or hindering (in which case, the player not knowing either works well)? In this case, potentially the consequences aren’t actually narrated straight after the test; for example, last session in @Mark_Watson’s game one of our group wrote an anonymous letter with the consequence of failure “the recipient realises it was you”; when they failed, Mark announced that they’d sent the letter and we moved on, then at the end of the session they get a letter from the person they wrote to demanding an immediate meeting.
Another aspect of discussion is how easy the group finds it to separate player from character when it comes to failure. There is a difference between the failing forward that BW draws interest from and being able to actively suggest meaningful failures. If the group are all fully comfortable with it, there’s huge advantage in having the whole group brainstorm failure for significant rolls; whereas, if not all the players are then having the GM take more of an impartial setter of consequences roll by not opening things for discussion can avoid people feeling socially required to be “nice” to other people’s characters.