Probes the limits of the feature-list architecture (Test 5 architecture, IP-claimed in Brief-for-Patent2-FeatureListCAD). Test 5 proved the architecture on a textbook mounting block (5/5 architecture, 100% content). Test 6 asks: where does it break? Five test parts of progressively higher difficulty. Each runs N samples; per-test architecture and content rates reported separately. Failures are categorised: architectural (the schema can't represent the part) vs implementation (schema OK, projection rules missing).