Fable 5.1 tops SWE-Bench, matching prior perf at 50% cost

ajratner · x · 2026-09-02

Claude Fable 5.1 now tops the Senior SWE-Bench leaderboard, edging out Fable 5 on the pass^3 tie-breaker by shipping quality code more consistently. Its best effort tier is Medium, and combined with cheaper cache reads, it matches Fable 5's performance at about 50% of the cost.

Related event: Fable 5.1 Tops Benchmarks but Costs More Per Task(16 posts)→

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