Claude Fable 5 outpaces GPT-5.5 by 13 points on FrontierMath's toughest problems

Anthropic's Claude Fable 5 achieved 88 percent accuracy on the hardest FrontierMath tier, surpassing OpenAI's GPT-5.5 by 13 points. The result marks a dramatic improvement from Anthropic's previous Opus 4.5 model, which scored below 10 percent in early 2026.

Anthropic's Claude Fable 5 hits 88 percent accuracy on the hardest FrontierMath tier, a massive jump from Opus 4.5, which sat below 10 percent in early 2026. OpenAI's GPT-5.5 reaches about 75 percent on the same tier. The pace of improvement in AI math keeps accelerating. The article Claude Fable 5 outpaces GPT-5.5 by 13 points on FrontierMath's toughest problems https://the-decoder.com/claude-fable-5-outpaces-gpt-5-5-by-13-points-on-frontiermaths-toughest-problems/ appeared first on The Decoder https://the-decoder.com .