OSWorld-Verified (Anthropic 361-task cohort)
Agents
The 361-task OSWorld-Verified cohort reported for Mythos 5, Mythos Preview and Opus 4.8 in Figure 8.16.3.A of Anthropic's Fable 5 and Mythos 5 system card. The figure reports pass@1 averaged over five runs, with 100 steps and max reasoning effort. Exact excluded task identities are not established, so this cohort is kept distinct from both the 369-task benchmark and other 361-task subsets.
Top models (higher is better)
| Model | Score |
|---|---|
| Claude Mythos Preview | 85.4 |
| Claude Fable 5 | 85.0 |
| Opus 4.8 | 83.4 |