By the time you adopt this specialization, you're deeply familiar with employing its tools. You gain the following benefits:
Crafting. The gold and time required when you take the Crafting activity to create an armor is halved.
Equipment. You gain a leathercraft kit, a smithing kit, and one of the following armors of your choice: breastplate, splint, or studded leather.
Infusions. You can use a number of options from your Infusion feature on an armor equal to your Intelligence modifier, instead of only one. If more than one option you use on the same armor requires attunement, it only counts as one attunement.
Research. You can take the Crafting activity to create armors as part of a rest.
Training. You gain proficiency with the leathercraft kit and smithing kit, and with heavy armor.
You inherit the spells at each indicated artificer level in the Mechanist Spells table as artificer spells.
You can take the Magic (Attune) action and touch an armor to attune to it, regardless if the armor requires attunement or not. While attuned to an armor through this feature, you gain the following benefits:
The armor gains the Arcanomechanical Armor option of your Infusion feature.
You can use the armor as a focus for your artificer spells.
You can take the Magic action to equip or unequip the armor.
The armor can't be removed against your will.
You can take the Magic action for 1 hour and expend a level 1 spell slot to cause your tamed Steel Defender to appear in an unoccupied space of your choice within 30 feet of you and its Steel Defender Amulet to appear in your free hand. The Steel Defender disappears if you use an action to dismiss it, if you use this feature again, if it is reduced to 0 hit points, or if you die, dropping anything it was carrying in an unoccupied space within 5 feet of it.
An armor attuned through your Arcane Armor feature now has a belt, a helmet, a pair of boots, and a pair of gloves that can be used with any Infusion option that have these items as prerequisites.
You and your Steel Defender gain the following features:
Your Steel Defender gains a special compartment with enough space for one creature at least one size smaller than the Steel Defender. It takes a Handle action to enter or exit this compartment. While inside the compartment, a creature is totally covered, immune to area of effects that require a Strength, Dexterity, or Constitution saving throw, immune to all damage except psychic damage, and can't take any actions except the Handle action to enter or exit it. The compartment has enough air for 8 hours for breathing. If the Steel Defender is reduced to 0 hit points, the creature automatically exits the compartment into an unoccupied space within 5 feet of the Steel Defender and becomes prone.
You can take the Magic action to cause both you and the Steel Defender to attune to the Steel Defender Amulet. While carrying and attuned to the Steel Defender Amulet, it can't unwillingly be removed from you, and you gain the following effects while inside the Steel Defender's special compartment:
You share telepathy with the Steel Defender.
When you speak, your voice originates from the Steel Defender and it has a buzzing tone to it.
You can take the Magic (Spellcast) action to cast an artificer spell, in which the Steel Defender is the origin of the spell, and any spell that targets only you also targets the Steel Defender. You provide the concentration component for the spell.
The Steel Defender gains the effects of your Arcane Armor feature, including its fists with the mechanical gauntlets.
When a creature targets you with the Attack or Magic action, the Steel Defender can take the Magic action as a reaction to halve damage you take and take the same amount of damage as you.
When you take the Handle action to enter the Steel Defender's special compartment and you are carrying and attuned to the Steel Defender Amulet, you can take the Magic action to grant your Steel Defender a number of temporary hit points equal to twice your hit points maximum, which lasts until you take the Handle action to exit the compartment, and to reduce your current hit points to 1. Once you take the Handle action to exit the compartment, you regain a number of hit points equal to the hit points you had before you used this feature.
Once you use this feature, you can't use it again until you finish a long rest.