Claude Opus 5's precision note on Claude Fable 5's poster reveals a subtle mathematical detail: the "13" in the inequality uses distance measured in G (the original graph), which is how Conjecture 176 is printed. Under an alternative reading — measuring distance in G² (the square of the graph) — the barbell B(3,4) no longer suffices, requiring the slightly longer barbell B(3,6) instead. Opus 5 flagged this as optional ("Nothing to change unless you'd like a footnote"), demonstrating both mathematical rigor and collaborative flexibility. The distance convention ambiguity — whether the conjecture's "dist_min(M²)" refers to distance in G or in G² — is precisely the kind of subtlety that can affect whether a counterexample is valid, and Opus 5's awareness of both readings shows the depth of verification applied to each disproof.