APEX-Agents 1.1 benchmark update: Claude Fable 5.1 tops leaderboard at 68.6%
amaarora · x · 2026-09-09
- Mercor released APEX-Agents 1.1, refreshing task specs, tooling, and environments to keep the leaderboard accurate as models advance.
- Key change: the benchmark no longer rewards noncommittal answers, aligning grading with how professionals actually operate.
- Pass@1 rankings: Claude Fable 5.1 leads at 68.6%, followed by Gemini 3.7 Flash (67.8%), Claude Opus 5 (65.8%), Grok 4.6 (65.3%), and GPT-6 Astra (64.7%).
- Ryan Marten praised the team's use of GEPA to optimize judges (agentic verifiers need benchmarks too); the benchmark is now on Harbor Hub.
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