RankingHumanity’s Last Exam
Humanity’s Last Exam
- Bucket
- Hard reasoning
- Unit
- percent
- Direction
- Higher is better
- Version
- —
- 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
Compare published benchmark results with category weights →
Models
| Model | Score | Harness | Evidence | Source-recorded date |
|---|---|---|---|---|
| Claude Fable 5.1Anthropic | 60.9%Reported settings & sourceFull2500questions; no tools; auto thinking;1Mtotal token cap; no compaction; Opus4.6grader; restricted fetch and contamination review for tools. 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 · Table 8.1.A;8.12.1 · reviewed 2026-09-12 | Claude Fable 5.1 and Claude Mythos 5.1 System Card | lab self-report | 2026-09-12 |
| Claude Fable 5Anthropic | 57.8%Reported settings & sourceFull2500questions; no tools; auto thinking;1Mtotal token cap; no compaction; Opus4.6grader; restricted fetch and contamination review for tools. 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 · Table 8.1.A;8.12.1 · reviewed 2026-09-12 | Claude Fable 5.1 and Claude Mythos 5.1 System Card | lab self-report | 2026-09-12 |
| Claude Opus 5Anthropic | 56.6%Reported settings & sourceFull2500questions; no tools; auto thinking;1Mtotal token cap; no compaction; Opus4.6grader; restricted fetch and contamination review for tools. Claude Fable 5.1 and Claude Mythos 5.1 System Card · Table 8.1.A;8.12.1 · reviewed 2026-09-12 | Claude Fable 5.1 and Claude Mythos 5.1 System Card | lab self-report | 2026-09-12 |
| Claude Fable 5Anthropic | 63.8%Reported settings & sourceFull2500questions; with tools; auto thinking;1Mtotal token cap; no compaction; Opus4.6grader; restricted fetch and contamination review for tools. 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 · Table 8.1.A;8.12.1 · 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 | 65%Reported settings & sourceFull2500questions; with tools; auto thinking;1Mtotal token cap; no compaction; Opus4.6grader; restricted fetch and contamination review for tools. 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 · Table 8.1.A;8.12.1 · reviewed 2026-09-12 | Claude Fable 5.1 and Claude Mythos 5.1 System Card | lab self-report | 2026-09-12 |
| Claude Opus 5Anthropic | 63.6%Reported settings & sourceFull2500questions; with tools; auto thinking;1Mtotal token cap; no compaction; Opus4.6grader; restricted fetch and contamination review for tools. Claude Fable 5.1 and Claude Mythos 5.1 System Card · Table 8.1.A;8.12.1 · reviewed 2026-09-12 | Claude Fable 5.1 and Claude Mythos 5.1 System Card | lab self-report | 2026-09-12 |