MaxxBench: models clustered at 74% on DeepSWE spread 23 points when tasks change slightly

dyn___ · x · 2026-11-08

MaxxBench reruns 89 DeepSWE coding tasks with small changes to instructions or starting code — same engineering problems, slightly different requirements. The result: models clustered around 74% on the original leaderboard end up 23 percentage points apart. On the chart, Claude Opus 5.5 tops MaxxBench at 76.4% with little degradation, followed by GPT-6 Astra at 71.9%, while GLM-5.3 (56.7%), DeepSeek V4.1 Flash (55.6%), Muse Spark 1.2 (38.8%) and DeepSeek V4 Flash (28.1%) lose far more — quantifying how much leaderboard performance is benchmaxing.

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