Cloaked Mage

Cloaked Mages are wizards who specialize in espionage and skullduggery. They are wizards who cast spells silently in the night, undetected. They specialize in working shoulder to shoulder with Assassins and Thieves. These Wizard/Rogue partnerships may be called "Cloaks and Daggers" in your setting. 

Knowledge of the Night

Beginning when you select this school at 2nd level, you gain proficiency with Stealth and Thief's Tools and you may add your Intelligence modifier to skill checks made with those proficiencies. You have also learned to speak Thieves' Cant. 

Cloak of Shadow and Magic

At 2nd level, instead of using personal spellbooks, Wizards of your college may use special cloaks of dark ribbons or elaborate magical fabrics with spells sewn into the linings. You gain proficiency with Weaver's Tools. Instead of inscribing spells into a book, you may add magical ribbons, stitching, or patches to a spell cloak. This can take whatever appearance you like. The cost of materials and time to add spells this way is the same as though you were adding them to a spellbook. Your spell cloak may be used as a spellcasting focus. 

Additionally, when you or an ally you can see within 30 feet of you takes damage, you may use your reaction to allow the target of the damage to vanish, turning invisible until the start of your next turn or until they make an attack or cast a spell. You may use this ability a number of times equal to your proficiency bonus and regain all uses on a long rest. 

Mute Casting

At level 6, you have mastered the mental craft of internalizing magical incantations. You may ignore the verbal components of spells.

You also learn the spells Pass Without a Trace and Silence if you don't already know them and add them to your spell cloak (or spellbook). 

Spell Thief

At level 10, you learn Counterspell and add it to your spellbook if you don't already know it.

Additionally, your Counterspells have a new effect. After successfully countering a spell, you may immediately expend the appropriate gp cost in materials the countered spell would cost to add to your spell cloak (or spellbook). The countered spell then appears in your spell cloak, but it must be prepared after a long rest as usual before you can cast it. In order for this special casting of Counterspell to work, the countered spell must be of a level you can cast. If the countered spell is not from the Wizard spell list, you instead create a spell scroll of the countered spell and add it to your inventory. 

Supreme Spell Cloak

At level 14, the amount of magic imbued into your cloak has given it special abilities. While wearing your cloak, you have a flying speed of 40 feet and can hover. You may also give your cloak to an ally to wear, granting them a flying speed instead. While not worn, your cloak has a flying speed of 60 feet and can hover and you may mentally control it's movement on your turn (no action required). 

Additionally, you may add the Dimension Door spell to your spell cloak if you don't already know it. Once per short rest, while wearing your spell cloak, you may cast Dimension Door without expending a spell slot. 

Lastly, your spell cloak shields you from sight. While wearing the spell cloak, you have advantage on Stealth checks.