Children’s independent activities within public spaces emerge as a fundamental condition for their development considered in the context of their needs: socialization, movement, autonomy, and enrichment of their creative, imaginative, and cognitive potential. The promotion of their independence represents a relevant issue for implementing the smart city paradigm. This paradigm calls for a methodological framework where the urban fabric’s performance is evaluated via comprehensive analytic protocols. The proposed study presents an audit tool for evaluating the quality of urban spaces in terms of their practicability by children: the Survey on Conditions of Practicable Environments (SCOPE). The practicability of this research is establishing the quality of urban spaces’ usability, and it is expressed in terms of compositional, configurational, functional, and social factors of the built environment organized within a framework articulated in seven key dimensions (connectivity, convenience, comfort, commitment, conviviality, conspicuousness, and coexistence). The introduction of the concept of practicability and of indicators incorporating the demand for a children-sensitive perspective in the project of public spaces determine the novelty of the SCOPE procedure. This methodology was applied to an area in Central Cagliari, Italy, to evaluate the usability of public spaces. The results reveal that the proposed methodology is relevant for implementing the smart city paradigm because it addresses children’s autonomy and their rights to the city by selecting and defining indicators to clarify and assess conditions of the built environment conducive to children’s autonomy and independent social activities.