FrontierCode’s design explains why Opus 5 scores drop as reasoning increases
silasalberti · x · 2026-07-25
The author explains why Opus 5’s FrontierCode scores can fall as reasoning effort rises.
FrontierCode is designed to measure merge-ability, not just correctness. It includes a scope criterion that penalizes edits beyond what the task actually requires. The same pattern appears across all frontier models tested, but it is most pronounced in Opus 5, which becomes more likely to refactor code unprompted at higher reasoning levels.
Related event: Opus 5 Peaks at Medium Reasoning in FrontierCode Tests(8 posts)→
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