Level 3
Mystic Spells.
Gain INT mana when you roll Initiative (lose ALL mana when combat ends). Choose 2 spells (tier 1 or lower) and 1 Utility spell.
Spellslinger.
(1/round) Free reaction: When you use Sneak Attack, cast a spell that would cost 2 or less actions to cast.
Level 7
Mystic Spells (2).
You can choose 2 spells (tier 2 or lower).
Level 11
Mystic Spells (3).
You can choose 2 spells (tier 3 or lower).
Level 15
Mystic Spells (4).
You can choose 2 spells (tier 4 or lower).