Choose a spell of 5th level or lower that you can cast, that has a casting time of or less, and that can target you.
You cast that spell—called the contingent spell—as part of casting contingency, expending mana for both spells, but the contingent spell doesn't come into effect. Instead, it takes effect when a certain circumstance occurs. You describe that circumstance when you cast the two spells. For example, a contingency cast with water breathing might stipulate that water breathing comes into effect when you are engulfed in water or a similar liquid.
The contingent spell takes effect immediately after the circumstance is met for the first time, whether or not you want it to, and then contingency ends.
In a quiet, deliberate motion, you touch the intricate figure that bears your likeness. Magic swirls, imbued into its carved form. The moment solidifies—the spell's future activation coded into its very being, a silent promise awaiting the precise trigger.