PsyTool is a European project, funded by Erasmus+ Sport Programme, led by the Universidad Pablo de Olavide (Sevilla, Spain). It brings together 13 partners from Spain, Portugal, Italy, United Kingdom and Sweden, running from January 2016 to December 2017. PsyTool is based theoretically on the concept of youth development through the practice of sport in positive and safe environments. The central idea is that this type of practice leads to a psychological wellbeing in all areas of personal development of athletes. Through sport programs that are free of bullying; zero permissiveness towards substance use; low acceptance of gamemanship and cheating, and at the same time promoters of fair play and clean competition, young athletes are more likely to increase their psychological well-being while they practice the sport to their best level of capacity. One of the most important assets of PsyTool is the formation of Agents of Change as inductors of this well-being promoter environment, according to their different responsibilities, from the politics to grassroot coaching. The AoCs’ selection, training and certification is one of the key points of this program. This so-called “targeted snowball” approach is expected to produce a spreading impact on the young athletes, which can be evaluated in the short and medium term, depending of the nature of the different AoCs. Coming form this design and theoretical background, this program –once the results have been analyzed- has to lead to a more ambitious development both in its scope and on the educational methods involved with.