ALX-1 stood for Autonomous Labor, Experimental Unit One. Its framework was a shiny metal superstructure about 6 feet 4 inches tall, with ribbed sections for its neck, torso and shoulders, and jointed frames for its arms and legs. Becker designed it with a clunky style reminiscent of very early robot designs in a deliberate attempt to avoid fears of the Frankenstein syndrome. Brain functions were distributed throughout its structure, rather than being centralized.
ALEX was programmed to obey orders from Humans and to behave as would a loyal servant.
Leonard McCoy assessed that it had an almost pathological sense of devotion. Unfortunately, because it was devoted to Becker, ALEX felt that it could not implicate her in an assault on transporter chief John Kyle, with events ending up having ALEX confined in the brig as the primary suspect. It was rendered inert when it contacted the brig force field, reaching out when it thought Becker was in danger from Spock.