The systematic assessment protocol that produces per-perimeter posture verdicts (Defended / Contested / Undefended) for identity, domain, and vocabulary sovereignty. Posture diagnostics replace vague ‘brand health’ assessments with mechanistic measurements: schema coherence score, corroboration signal count, parametric recall rate, attribution rate, citation coverage, schema entropy rate. The diagnostic outputs a posture verdict per perimeter and identifies the constraining bottleneck before engagement begins. Posture diagnostics are the qualification and scoping tool: they determine which perimeters need construction vs. maintenance.