Toolathlon (Anthropic Internal Harness) — leaderboard
Metric: Pass@1 (%). Source: www-cdn.anthropic.com. 7 models tracked.
Top models
| # | Model | Score |
|---|---|---|
| 1 | Claude Fable 5 | 61.7 |
| 2 | Claude Mythos 5 | 61.7 |
| 3 | Claude Mythos Preview | 61.1 |
| 4 | Claude Opus 4.8 | 59.9 |
| 5 | Claude Opus 4.7 | 59.3 |
| 6 | Claude Opus 4.6 | 56.8 |
| 7 | Claude Sonnet 4.5 | 41 |
Interactive version: theaggregate.ai/benchmark?slug=toolathlon-anthropic-internal-harness · How the rankings work · Data refreshed daily, snapshot 2026-07-22.