You are considered a Humanoid and a Construct. If a spell that wouldn’t affect constructs targets you, you are affected as usual. 

Due to your metallic nature, your body is naturally more resistant to attacks. Your AC while unarmored is equal to 13 plus your Dexterity modifier. 

Mechanical Nature. 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, or breathe.

Sentry's Rest. 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 aren't unconscious.

You know the Mending cantrip and can cast it without material components. Constitution is your spellcasting modifier for it.