Opus 5 Scored 53.4% on FrontierCode at Launch, Just 48% on the 5.5 Card

mathemagic1an · x · 2026-09-23

Andrew Carr flagged that Opus 5 reported 53.4% on FrontierCode at launch but shows 48% on the same eval's 5.5 card — prompting the coinage "Benchflation": benchmark updates silently rewriting historical scores and eroding leaderboard comparability.

Related event: Opus 5 FrontierCode score drops from 53.4% to 48% in new card(2 posts)→

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