This document discusses three approaches to persuasive technology design: external shaping of behavior, self-managed behavior change, and self-shaping. It presents three formative studies on self-tracking and behavior change, user-generated self-shaping designs, and features that support self-shaping. The studies found that self-shaping is a function of the individual rather than the tool; self-shaping designs are more personalized with clearer behavioral intentions; and tools vary in flexibility of self-shaping use and how salient self-shaping features are. The conclusion is that self-shaping and commitment devices are not clearly conceptualized, and users attribute behavior change primarily to self-discipline rather than tools.