Post-Publication Addendum: Developmental Vulnerability Windows and Platform Design Obligations

This document is a post-publication addendum providing an operational clarification of the algorithmic reconditioning framework developed across three related works by the author. It does not introduce new concepts, empirical evidence, or analytical claims. Its purpose is to translate developmentally grounded vulnerability windows—implicit in the formation-level analysis—into differentiated platform design obligations, in order to support interpretation, implementation, and policy application of the existing framework. The addendum focuses on adolescence as a period of heightened neurodevelopmental plasticity, during which engagement-optimising interaction architectures can generate cumulative formation-level risk. It clarifies how such risks map to architecture-level responsibilities, emphasising system design rather than individual user attribution. The framework is technology-neutral, jurisdiction-agnostic, and intended to complement existing digital governance instruments without proposing new statutory mandates. This addendum should be read in conjunction with Algorithmic Reconditioning and Adolescent Formation, Youth Digital Governance in ASEAN, and The Global Covenant for Youth in the Digital Age, to which it serves as a formal interpretive supplement.