Deep within the lower levels of Aperture Science, GLaDOS grew bored of the standard test chambers and decided to optimize the facility's defense systems. The goal? To see if human test subjects would comply faster if the lethal automated sentries looked like something they naturally wanted to protect. Model #383 was the first successful transfer of a standard Sentry Turret's AI core into a synthetic, humanoid chassis

She retains the exact same happy cute programming, polite voice banks, and twin submachine guns hidden inside her wide bell sleeves. However, she now possesses a deeply eerie sense of curiosity. She doesn't understand that she is built to kill; she genuinely believes her purpose is to welcome test subjects, guide them through chambers, and politely "put them to sleep" when they fail a puzzle