Automatrons are specially crafted companions designed by the Sole Survivor to suit their own personal needs. They can be created, upgraded and renamed at a robot workbench, provided the resource requirements are met. They start with protectron parts without any armor, but individual parts from other robots can be scavenged and attached, and upgraded further with quality armor attachments to meet (or exceed) factory quality.

Created automatrons can have 1 of 9 different voices, many with similar functionalities. All automatrons start with the male voice selected.

The first four similar voices are the male, female and the relative processed variants of each. The voices all sound like well spoken servants, with the normal variation sounding like well recorded voices and the processed variants sounding more mechanical and modified. This voice type has personality subroutines that can be activated by selecting yes when requested when the robot is first created or by navigating through dialogue when the automatron is the current follower. These voice types are the only voice types that allow one to command the robot to self destruct, this is accomplished by navigating to the self destruct dialogue and giving the requested secondary confirmation, the unit will then begin the self destruct sequence and count down from ten, then it will explode.

Another set of similar voices are the assaultron and sentry bot voices, both have the same voice lines, and they both mimic the voices of the respective robots. When asked to initiate personality subroutines both voices also respond with "ERROR, command not recognized," although there are cases of both sentry bots and especially assaultrons with personalities; they respond the same when asked to self destruct.

The last 3 voices are different sounding beeps and clicks (beep-click, beep-dark and beep-bright), robots with these voices appear to exhibit emotion, but have no programmed personality subroutines in-game, other robots may be heard exclaiming something along the lines of "your personality appears to be an error in your program, have you considered having it purged." Robots with this voice type will respond with a (negative beep) when asked to self destruct. Which means it is impossible for automatrons with the last 3 voices to self-destruct.

Automatrons will almost always fight on the side of the Sole Survivor, but may turn against them if they attack a settlement that the robot is a part of or was recently part of, even if they are the Sole Survivor's current companion.