Claude Fable 5 is strong on ZeroBench, but not a clear breakthrough
23% pass@5 (tied SOTA)
8% pass^5 (SOTA 10%)
3.6% refusal rate
For comparison, other recent releases (pass@5 / pass^5):
Opus 4.8: 17 / 4
Gemini 3.5 Flash: 19 / 5
A good result, but still plenty of headroom