FATE actions are not "graven in stone" until the GM narrates the results. There is, in FATE (and many other narrativist games) a clear distinction between mechanic and narrative - at least in play. And the task attempt description is mechanic, not narrative, until the outcome is agreed upon.
Noting that SOTC p 11 makes it clear that aspects are invoked after rolling:
Invoke an Aspect: When you have an aspect that's applicable to a situation, it can be invoked to grant a bonus. After you have rolled the dice, you may pick one of your aspects and describe how it applies to this situation. If the GM agrees that it's appropriate, you may spend a fate point and do one of the following:
- Reroll all the dice, using the new result, or
- Add two to the final die roll (after any rerolls have been done).
You may do this multiple times for a single situation as long as you have
multiple aspects that are applicable. You cannot use the same aspect more
than once on the same skill use, though you may use the same aspect on
several different rolls throughout a scene, at the cost of one fate point per
use.
The example on page 11 also shows that the description of the action before rolling is mutable - notice the fourth paragraph of the following quote, where Jet is trying to get the bomb away before it goes off:
Example: Jet Black has the aspects “Nick of Time”, “Seat of My Pants”
and “Motorhead”. He’s just grabbed the ticking bomb and is trying to
sprint out of Tesla’s lair in time to toss it off the cliff.
Jet has Superb Athletics, but he rolls terribly ––=– (-3) for a result of
Fair (Superb - 3), which is far from good enough. He points out that he’s
doing something crazy “by the seat of his pants,” and the GM thinks that’s
fine, so Jet spends a fate point to reroll the dice. He does a little better,
––+– (-2) for a result of Good (Superb - 2).
Still, he’s worried it’s not quite good enough, so he suggests that as a
Motorhead, he knows things about machinery, like… like bombs! That
might be useful…!
The GM tells Jet that she feels that his engineering knowledge is not going
to be much use unless he wants to stop to try to defuse the bomb – is that
what he’d like to do?
It should be noted that the engineering knowledge comes from the aspect Motorhead, not from an engineering skill. This is a valid use of Aspects... representing a knowledge base that applies narrowly to any given skill, but to several skills.
As the example shows, even after rolling and then invoking one aspect, the nature of the task can be altered with aspects.
It's also worth pointing out that failure on a throw means a different bunch of story effects than a failure on a defuse... namely where it goes off. A fail on the sprint means it's still moved, but not enough to save Jet; a failed defuse means it goes off right where it was, and we can presume that would be bad... very bad.