The bill proposes significant amendments to Massachusetts child custody law by replacing Chapter 209B with the Massachusetts Uniform Child Custody Jurisdiction and Enforcement Act. This new chapter introduces comprehensive definitions related to child custody, establishes jurisdictional guidelines emphasizing the child's home state, and outlines procedures for inter-state court communication and emergency jurisdiction cases. It clarifies the conditions under which Massachusetts courts can modify custody determinations from other states and emphasizes the need for cooperation between courts, as well as the preservation of custody-related records.

Additionally, the bill includes provisions for enforcing child custody determinations from other states, mandates prompt hearings in cases where a child is at risk, and specifies conditions under which a court may issue a warrant for taking physical custody of a child. Key insertions include the requirement for courts to award necessary expenses to the prevailing party and the authority for prosecutors or public officials to take lawful actions to locate or return a child in cases of wrongful removal. The act is set to take effect on December 31, 2025, and includes a severability clause to ensure the enforceability of remaining provisions if any are found invalid.