Feat: Magical Understudy
Your eidolon evolves to cast spells. They gain the Cast a Spell activity and learn two cantrips of their tradition, which they can cast as innate spells.
Pathfinder 2e Database
Your eidolon evolves to cast spells. They gain the Cast a Spell activity and learn two cantrips of their tradition, which they can cast as innate spells.