RankingToolathlon · Verified June2026
Toolathlon · Verified June2026
- Bucket
- Supporting evidence
- Unit
- index
- Direction
- Lower is better
- Version
- Verified June2026
- Display harness
- Claude Fable 5.1 and Claude Mythos 5.1 System Card
- Board
- https://www.anthropic.com/claude-fable-5-1-mythos-5-1-system-card
The available records have no admitted matched comparison in the capability core. Raw results remain available below.
Compare published benchmark results with category weights →
Models
| Model | Score | Harness | Evidence | Source-recorded date |
|---|---|---|---|---|
| Claude Opus 5Anthropic | 23.5 turnsReported settings & sourceaverage turns;108tasks/three trials; internal harness; max effort; Fable safeguards+Opus4.8fallback; Opus safeguards/fallback disabled; pinned containers/data. Claude Fable 5.1 and Claude Mythos 5.1 System Card · Table8.15.5.A · reviewed 2026-09-12 | Claude Fable 5.1 and Claude Mythos 5.1 System Card | lab self-report | 2026-09-12 |
| Claude Fable 5.1Anthropic | 23.7 turnsReported settings & sourceaverage turns;108tasks/three trials; internal harness; max effort; Fable safeguards+Opus4.8fallback; Opus safeguards/fallback disabled; pinned containers/data. Fable is the safeguarded deployed configuration; selected tasks may use disclosed Opus fallback, except evaluations explicitly counting safety blocks as failures. Claude Fable 5.1 and Claude Mythos 5.1 System Card · Table8.15.5.A · reviewed 2026-09-12 | Claude Fable 5.1 and Claude Mythos 5.1 System Card | lab self-report | 2026-09-12 |