Roberta's bio is available in the minor character docket and is as follows:

Roberta is an android girlfriend created by Chester and secretly a Decepticon. In fact, she routinely quotes Megatron throughout her season one debut, "Re-Animate Me (On the Dance Floor)." She only appears for this episode and is destroyed by Nikki after performing an absolutely terrifying dance number. It remains a belief, however, of the robot servants heard throughout the series that Roberta lives on as their prophet.