You have Darkvision with a range of 60 feet.

You have resistance to poison damage and immunity to disease, and you have advantage on saving throws against being paralyzed or poisoned. You don’t need to eat, drink, breathe or sleep, and magic can’t put you to sleep.

Due to the source of your strange nature as a Feenstein Automata you do not regain Hit Points, Hit Dice, or Spell Slots as the result of a Long rest. Additionally, you are unable to regain Hit Points from any class feature or spell you possess, unless you expend a Hit Dice to do so.  

You are able to be affected by spells that don't normally affect Constructs, such as Cure Wounds, Healing Word, Spare the Dying, or Hold Person. But any healing you receive from those sources is reduced by half.

You innately know the Mending cantrip (Intelligence is your spellcasting ability for it), and if Mending spell is cast on you, you can spend a Hit Die, roll it, and regain a number of Hit Points equal to the roll plus your Constitution modifier (minimum of 1 hit point). 

To regain Hit Points, Hit Dice, or Spell Slots you must consume Feenstein or a similar substance. 

Feenstein Consumption
To consume shards of Feenstein takes an amount of minutes (per Feenstein shard) equal to double your proficiency bonus, after which point you may choose one of the following benefits per shard consumed. 

• You may regain an amount of spell slots with a combined level equal to your proficiency bonus (per Feenstein shards consumed).  
• You may regain a number of Hit Dice equal to your proficiency bonus (per Feenstein shard consumed).
  • When choosing this option, all non spellcasting features that recover at the end of a short rest are restored.
  • If you choose this option during a Long Rest you may immediately roll any number of those Hit Dice to regain a number of Hit Points equal to the roll plus your Constitution modifier. 

You gain one skill proficiency and one tool proficiency of your choice.

When you take a long rest, you spend at least 6 hours in an inactive, motionless state, instead of sleeping. In this state, you appear inert, but you remain conscious.

Your body has built-in defensive layers, which can be enhanced with armor:

• You gain a +1 bonus to Armor Class.
• You can don only armor with which you have proficiency. To don armor other than a shield, you must incorporate it into your body over the course of 1 hour, during which you remain in contact with the armor. To doff armor, you must spend 1 hour removing it. You can rest while donning or doffing armor in this way.
• While you live, the armor incorporated into your body can’t be removed against your will.