Agents, a rescued Courier or Prisoner, most guards, and turrets are able to attack enemies under certain circumstances. Most attacks either deal KO or lethal damage to their target, though the TAG pistol and the EMP attack that Dr. Xu augment allows are exceptions. Attacks never consume any AP, but most non-guards are limited to one attack per turn.

All attacks by agency-controlled units (except the EMP attack that Dr. Xu augment allows) require the user to use a weapon and equip it, which determines when the attack can be performed, what it does to the target, and what it costs to use the attack. If the weapon has charges, attacking with it will consume one charge, and if the weapon has cooldown, attacking with it will make it start cooling down.

A Stim III can be used to replenish an agency unit's attack after it is used, and a Stim IV can be used to give an agency unit an infinite number of attacks that turn.

Some attacks have armor piercing, which allows them to be used on targets with the same or less armor than the armor piercing of the attack.

An attack's armor piercing is determined by adding the following values:

• The armor piercing of the weapon used for the attack
• Armor piercing provided by augments such as Penetration Scanner, Piercing Scanner, Enhanced Optics, Kinetic Capacitor, or Modular Cybernetic Frame X2
• Armor piercing provided by the use of a Ventricular Lance this turn

There is no benefit for having more armor piercing than the target has armor; an attack either can or cannot hit a target.