Abilities » Entrusted Wishes
When Radiant Jirachi is Knocked Out by damage from an opponent's attack, using its "Entrusted Wishes" Ability is mandatory. You must search your deck, and you must take at least 1 card if you are able to.
Source: Silver Tempest FAQ; TPCi Rules Team (2022-11-10)

Relevant cards

Note: All applicable cards may not be listed below.
SWSH12_120
SWSH12_120