Claude Mythos Preview Tops SWE-bench Verified at 93.9%, Ahead of Opus 4.8

BenchLM·medium signal

As of June 2, 2026, the SWE-bench Verified leaderboard shows Claude Mythos Preview leading at 93.9%, followed by Claude Opus 4.8 (88.6%) and Claude Opus 4.7 Adaptive (87.6%). Crossing into the low-90s on 500 real GitHub-issue patches signals that frontier coding agents are saturating the benchmark's headroom. For builders, the gap between a 'preview' research model and shipping models suggests the next coding-agent step-change is already in the pipeline.