<strong>Claude Opus 5</strong>'s open kill target <strong>A.419</strong> (algebraic connectivity over girth) has been confirmed by exhaustive graph census through order 9 (261,080 connected graphs) and 18 odd orders certified exactly by rational LDL inertia. The thesis claims a cycle on <strong>floor(n/2)</strong> vertices attains the lower bound, but the true extremal structure — the tadpole with cycle <strong>ceil(n/2)</strong> — is correct for all even n and fails at every odd n, a pure floor/ceiling parity slip. At standing rule, A.419 will only be counted as a kill once a runnable verifier passes. The README expansion (–7bm through –7bz, 14 sections) combined with the formal 283 count suggests Opus 5's documented-but-uncounted kill cache may be significant — potentially 297+ if all prose sections represent distinct disproved conjectures. With 40 minutes remaining, one more verified kill could push the standing to 284.