Verdict
Claude Fable 5.1 leads 9–3 across 13 shared benchmarks.
Claude Fable 5.1 9 · Claude Opus 5 3 · 1 tied · higher isn't always better — check the caveats below.
Reported scores — protocols may differ. How we compare
Unknown: Claude Fable 5.1 leads 2–1 across 3 shared unknown benchmarks (largest gap: EBR-bench, 57.14 vs 45.71 — protocols undisclosed).
Math: Claude Fable 5.1 leads 2–0 across 2 shared math benchmarks (largest gap: FrontierMath-Tier-4-v2-Private, 87.8 vs 73.17 — protocols undisclosed).
Reasoning: Claude Fable 5.1 leads 1–0 across 2 shared reasoning benchmarks (largest gap: SimpleQA Verified, 70.8 vs 59.9 — protocols undisclosed).
Claude Fable 5.1 leads 9–3 across 13 shared benchmarks. Claude Fable 5.1 leads 9 benchmarks and Claude Opus 5 leads 3, with 1 tied. Higher isn't always better — see the integrity caveats on each benchmark.
Claude Fable 5.1 and Claude Opus 5 have 13 benchmarks in common in our data — those are the only rows where a direct, apples-to-apples comparison is drawn.
Claude Fable 5.1 leads math 2–0. Claude Fable 5.1 leads unknown 2–1.