You have always been curious of how things work.  Disassembling things to see the individual parts helped you understand the fundamental way each one and the part they play in the overall functionality.  After being exposed to the arcane, you found that the weave of magic can be similarly disassembled and reassembled.  Through time and study and trials and failures, you begin to get a grasp of how to dissect and enhance the magical properties of objects and spells.  

Mr. Fix-It

When you choose this subclass at 3rd level, you gain the ability to cast the spell Mending without material components.  Also, by expending a spell slot, you may cast it instantly instead of as a ritual.  

Diagnostics

 At third level, you gain the ability to diagnose why a magical spell or ability succeeds or fails.  When a target that you can see within 30 feet succeeds or fails a saving throw, you may use your reaction to cause the target to reroll that save and take your choice of the higher or lower of the two rolls.  You may use this feature a number of times per long rest equal to your intelligence modifier. 

Spells

Additional spells granted at 3rd level

Spells - 5th

Spells granted at 5th level

Supercharger

 At 5th level you may use your Mr. Fix-It ability as a bonus action.  The range of your Diagnostics ability is extended to 60 feet and grants your choice of advantage or disadvantage to the new roll.  When a target you can see within 30 feet is affected by a spell, you may use your reaction to expend one spell slot and cause the spell to be cast as though one level higher.

Repair Tech

At 9th level your Mr. Fix-It ability allows you to mend magical items and allow them to retain their magical qualities.  Roll a D20 and add your Arcane skill modifier to the roll to determine the success of the repair.  The DC is based on the rarity of the magic item: Common = 10, Uncommon = 15, Rare = 20, Very Rare = 25, Legendary = 30.  If this ability is done as a ritual, you may double your proficiency modifier when rolling. 

     Tune-Up - As a bonus action, you may touch an item and expend a spell slot to add an addition die of any type that the items properties would incur.  This effect lasts a number of rounds equal to the level of the spell slot expended.  You may also remove a magical effect from an item by using a bonus action to touch the item.  This effect lasts a number of rounds equal to the level of the spell slot expended.

Spells - 9th

Spells granted at 9th level

Spells - 13th

Spells granted at 13th level.

Arcanical Inclination

At 15th level, as a ritual, you may transfer or remove a magical enchantment from an item.  The enchantment must be transferred to a new item before the ritual ends or the enchantment is lost.  If the target of this ability is a curse, it will attach itself to you if no item is available to transfer the curse to.  Once an enchantment is removed from an item, it can no longer be affected by the same enchantment.  When performing this ability, you may roll a D20 and add your Arcana skill modifier to the roll.  On a success, you learn how to cast the enchantment and what components are needed for it.  The DC for the check for this ability is determined by the rarity of the enchanted item.  Common = 10, Uncommon = 15, Rare = 20, Very Rare = 25, Legendary = 30

Spells - 17th

Spells granted at 17th level