Robe of the Archmagi

Wondrous item, legendary (requires attunement by a sorcerer, warlock, or wizard)

This elegant garment is made from exquisite cloth and adorned with runes.

You gain these benefits while wearing the robe.

Armor

If you aren’t wearing armor, your base Armor Class is 15 plus your Dexterity modifier.

Magic Resistance

You have Advantage on saving throws against spells and other magical effects.

War Mage

Your spell save DC and spell attack bonus each increase by 2.

Source: Dungeon Master’s Guide (2024) p. 298. Available in the SRD and the Free Rules (2024)