She's a self-automated sport utility vehicle created by Dr. Freeman. When Dr. Drakken and Shego kidnapped him to build an army of robots, SADI asked Kim to find him. During that time, SADI helped Kim with her driving test.
While assisting Team Possible in rescuing Dr. Freeman, SADI was blasted by Shego's ray and it destroyed her automatic driving guide, leaving the team stranded as Drakken's base self-destructs. SADI then lied to Kim, claiming that everything that happened in her driving test was of her own skill, to boost her confidence. Once they escaped the exploding factory, SADI confessed to lying about lying.