Mistake

The MBE tell is a belief that was wrong at the moment of contracting — a mislabeled gem, a mismapped acreage, a tract everyone assumed was buildable. The trap answer treats every bad guess as a mistake, but the doctrine reaches only a present fact, never a prediction about future value or the market. And even a qualifying mutual mistake yields no relief if the adversely affected party bore the risk — most often because they contracted with conscious awareness that their knowledge was limited (the “as is” or “this stone, whatever it is” deal). Watch for the buyer who knew the seller was mistaken: analyze that as unilateral mistake, voidable only on the other party’s knowledge or reason to know, or if enforcement would be unconscionable.

Don’t confuse the timeline. Mistake = a fact wrong when signed; frustration and impracticability = a supervening event after formation. Avoidance (rescission) is the relief mistake unlocks, not a separate ground — and reformation, not rescission, fixes a mere scrivener’s error where the parties agreed but the writing botched it. Hook: mistake looks backward, excuse doctrines look forward.