Text-message-based parenting programs have proven successful in improving parent engagement and preschoolers’ literacy development. This study seeks to identify mechanisms of the overall effect of such programs. It investigates whether actionable advice alone drives previous studies’ results and whether additional texts of actionable advice improve program effectiveness. The findings provide evidence that text messaging programs can supply too little or too much information. A single text per week is not as effective at improving parenting practices as a set of three texts that also include information and encouragement, but a set of five texts with additional actionable advice is also not as effective as the three-text approach. The results on children's literacy development depend on the child's pre-intervention literacy skills. For children in the lowest quarter of the pretreatment literacy assessments, providing one example of an activity improves literacy scores by 0.19 standard deviations less than providing three texts. Literacy scores of children in higher quarters are marginally higher with only one tip per week than with three tips per week. We find no positive effects of increasing to five texts per week.