HLE-Diamond - Reasoning: leaderboard

The 500 reasoning questions of HLE-Diamond, CAIS and Scale AI's refined 1,000-question Humanity's Last Exam subset; closed-book accuracy without tools.

Metric: Accuracy (%, 500 reasoning questions, no tools). Source: lastexam.ai. Saturation forecast: Around February 2027. 32 models tracked.

Top models

#ModelScoreOverall rank
1GPT-6 Astra (Max)80.8#6 (GPT-6 Astra)
2GPT-6.1 Sol (Max)75.4#10 (GPT-6.1 Sol)
3GPT-6 Astra (High)74.2#6 (GPT-6 Astra)
4Claude Opus 5.5 (Max)68.6#5 (Claude Opus 5.5)
5GPT-6.1 Sol (High)67.4#10 (GPT-6.1 Sol)
6Claude Fable 5.1 (Max)62.6#14 (Claude Fable 5.1)
7Claude Opus 5.5 (High)62.4#5 (Claude Opus 5.5)
8Gemini 4 Argon (High)61.8#11 (Gemini 4 Argon)
9Claude Fable 5.1 (High)61.8#14 (Claude Fable 5.1)
10GPT-6 Sol (Max)57.2#24 (GPT-6 Sol)
11Claude Sonnet 5.5 (Max)54#18 (Claude Sonnet 5.5)
12GPT-5.6 Sol (Max)53.2#29 (GPT-5.6 Sol)
13Muse Wonder (Max)51.4#27 (Muse Wonder)
14Kimi K3.1 Pro (Max)47#28 (Kimi K3.1 Pro)
15Claude Opus 5 (Max)46.2#20 (Claude Opus 5)

No result here: #1 Claude Fable 5.2, #2 Gemini 4 Carbon.

Interactive version: theaggregate.ai/benchmark?slug=hle-diamond-reasoning · How It Works · Data refreshed daily, snapshot 2026-11-12.