Play is the most critical job of a child: it is fun, but also involves learning and training collaboration. The social skills needed to collaborate are the most sought-after socio-emotional competencies for the 21st-century but are often overlooked in educational systems worldwide. Social robotic technology could play a significant role in supporting children’s collaborative skills if designed in a responsible and developmentally appropriate fashion. What if the technology we design for children could nurture social skills through play? What if toys could support collaboration through play in a developmentally appropriate way? This work is a form of transdisciplinary responsible design of technology, wherein roboticists, designers, and children work together.