Claude Fable 5 outpaces GPT-5.5 by 13 points on FrontierMath's toughest problems
Quick Answer
Anthropic's Claude Fable 5 achieves 88% accuracy on FrontierMath's toughest problems, surpassing OpenAI's GPT-5.5 by 13 points at 75%.
Quick Take
This significant improvement marks a leap from Opus 4.5's sub-10% performance in early 2026, highlighting the rapid advancement in AI math capabilities.
Key Points
- Claude Fable 5 scores 88% on FrontierMath's hardest problems.
- OpenAI's GPT-5.5 achieves 75% accuracy on the same benchmark.
- Fable 5 outperforms GPT-5.5 by a notable 13 points.
- Opus 4.5 had less than 10% accuracy in early 2026.
- AI math performance is improving at an accelerating pace.
Source Excerpt
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.
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