RankingMILU

MILU

Data updated 12 Sept 2026

Bucket
Knowledge
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

ModelScoreHarnessEvidenceSource-recorded date
Claude Fable 5.1Anthropic93%
Reported settings & source

Mean accuracy11languages; adaptive max; five trials; no tools/custom system prompts.

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 · 8.18.2 · reviewed 2026-09-12

Claude Fable 5.1 and Claude Mythos 5.1 System Cardlab self-report2026-09-12
Claude Fable 5Anthropic92.9%
Reported settings & source

Mean accuracy11languages; adaptive max; five trials; no tools/custom system prompts.

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 · 8.18.2 · reviewed 2026-09-12

Claude Fable 5.1 and Claude Mythos 5.1 System Cardlab self-report2026-09-12
Claude Opus 5Anthropic92.1%
Reported settings & source

Mean accuracy11languages; adaptive max; five trials; no tools/custom system prompts.

Claude Fable 5.1 and Claude Mythos 5.1 System Card · 8.18.2 · reviewed 2026-09-12

Claude Fable 5.1 and Claude Mythos 5.1 System Cardlab self-report2026-09-12