"If the successes equal or exceed the obstacle, the character has succeeded in his goal – he achieved his intent and completed the task.
“This is important enough to say again: Characters who are successful complete actions in the manner described by the player. A successful roll is sacrosanct in Burning Wheel and neither the GM nor other players can change the fact that the act was successful. The GM may only embellish or reinforce a successful ability test.”
BWGR, Page 30; emphasis mine.
Seperating Intent and Task is a technique the GM can use to arbitrate failure. The GM doesn’t get to touch my successful fucking roll other than to say how cool it is.
Me: My intent is to prevent him from interfering with my friend completing the ritual. My task is to grab him in a choke hold, wrestle him to the ground, and subdue him.
GM: Great. A vs Power test.
The Dice: You win, Quincy.
The GM: Cool, so you guys wrestle a bit, and it’s clear that you’ve got the upper hand. He breaks away and runs into the night, leaving your friend to complete the ritual.
Me: No he fucking doesn’t.
No he fucking doesn’t.
My charcater performs the action as I describe; he completes his task. The guy is subdued; he can’t get away. It doesn’t matter that the GM is technically giving me my intent; they can’t undermine the success of my roll and take my successful task away from me.
Testing is about failure being interesting, not the task being hard. Ob 1 tests can have wonderful failure results, so you test against Ob 1 sometimes. Sometimes things that are incredibly difficult just don’t have meanigful consequences if failed; you just say yes and move on.