You touch a willing creature who isn't wearing armor and a protective magical force surrounds it until the spell ends. The target's base AC becomes 13 + its Dexterity modifier. The spell ends if the target dons armor or if you dismiss the spell as an action.
Additionally, once you cast this spell on a creature, you may recast this spell on that creature using an Action without expending a spell slot.
You may recast this spell on that creature as many times as you wish until you complete a Long Rest. After a Long Rest, you will need to expend a spell slot to cast this spell on that creature again.
You have learned to regain some of your magical energy by studying your spellbook.
When you finish a short rest, you can choose expended spell slots to recover and change out some of your prepared wizard spells.
The spell slots can have a combined level that is equal to or less than half your wizard level (rounded up), and none of the slots can be 6th level or higher.
You may swap out a number of your prepared spells equal to half your proficiency bonus (rounded up) with other spells that are already in your spellbook.
Once you use this feature, you may not use it again until you complete a Long Rest.