These contracts appear in full in Winter Masques page 47.
Though the changeling can sense any vow, only the stronger ones are useful for the later clauses of this contract. For those powers, the subject must be pursued for or accused of a vow more significant than, say, jaywalking, speeding, or breaking a software EULA.
By book, the third clause of the Contracts of Oath and Punishment is really wimpy: it gives you resistance against emotional manipulation, but only if that manipulation comes from a court contract. This level of power could fit a one dot clause, but not one which warrants three dots.
So, now the bonus from the clause applies against any form of emotional manipulation, no matter the source. If someone is trying to sway your emotions, Oath and Punishment 3 helps. Fleeting court contracts and things like Smoke 1 are also resisted by this clause.
To use this clause, the changeling must know some details of a pledge or oath that the subject has broken. Old-fashioned investigation can find enough out fairly quickly, and an exceptional success on Sense Tainted Vows (••) provides plenty of detail all on its own.