The mandatory reporting system of children at risk of harm is a cornerstone in the Swedish welfare state’s ability to identify, support, and protect children. This system continues to expand, involving an increasing number of children. This article maps the implications and processes involved in making the mandatory reporting system meaningful for identifying children at risk and enabling collaboration between the police and child welfare services. It does so in light of current political discussions and development efforts on early interventions and coordinated activities between welfare sectors. Drawing on interviews with 17 professionals from the police, child welfare services, and strategic positions involved in initiatives to enhance collaboration between welfare organizations, the article reveals that the mandatory reporting system is a double-edged sword. It is considered a necessary tool for safeguarding children in need and an important societal statement of children’s right to protection and support. At the same time, the system is perceived as a challenging entry point for the changing capacity of social work, creating ambiguities for professionals who find themselves navigating a system where it is nearly impossible to act correctly. Current development initiatives are intended to address the system’s flaws by creating an interface that promotes close collaboration between welfare sectors and facilitates earlier identification of children in need. However, these efforts introduce new challenges, particularly regarding what kind of worry police are supposed to report to child welfare services and the capacity of the mandatory reporting system.