FrontierCode (Diamond)

Hardest FrontierCode subset (early version reported at Claude Fable 5 launch).

% solvedHigher is betterCounts toward:Weights: Coding ×0.5The test's websiteOfficial page ↗

The best 2 · 2 models tested

Top 2 · best setting per model · 2 models, 2 results (0 independent)

Measured by independent testersIndependent Reported by the makerVendor-reported

FrontierCode (Diamond) leaderboard
				Thinking levelSetting
1	Claude Fable 5	Anthropic	29.3%	Extra highadaptive thinking, effort=xhigh	Maker's own figureVendor-reportedAnthropic ↗	Claude Code	9 Jun 2026
2	Claude Opus 4.8	Anthropic	13.4%	Extra highadaptive thinking, effort=xhigh	Maker's own figureVendor-reportedAnthropic ↗	Claude Code	9 Jun 2026