Claude Fable 5 outpaces GPT-5.5 by 13 points on FrontierMath's toughest problems
Signal
78
Hype
35
In three linesAnthropic's Claude Fable 5 achieves 88% accuracy on FrontierMath's hardest tier, versus 75% for OpenAI's GPT-5.5. Massive jump from Opus 4.5 (< 10% early 2026).Read source
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Summary generated by Claude — human-verified