Structural Selection and Boundary Diagnosis

This work presents a structural selection and boundary diagnosis framework for the attribution of physical effectiveness under extreme conditions. The contribution is strictly methodological. It introduces neither new dynamics, degrees of freedom, nor ontological assumptions and does not modify established field equations. The framework makes explicit the structural conditions under which formal contributions may be counted as physically effective. Divergences, representation dependence, and unbounded scaling behavior are interpreted as symptoms of inadmissible counting assumptions rather than as indicators of missing physics. A pre-dynamical diagnostic protocol is formulated, specifying criteria such as scale binding, structural finiteness, representation invariance, robustness, and boundary compatibility. Illustrative applications to vacuum energy in quantum field theory and trans-Planckian contributions in Hawking radiation demonstrate how structurally consistent restrictions of physical effectiveness restore physical interpretability while leaving established low-energy physics unchanged. The work is intended as a general diagnostic tool for structural consistency analysis in quantum field theory, semiclassical gravity, and related areas.