Claude Fable 5
Claude Fable 5 is the first public Mythos-class model, priced at $10/$50, with classifiers that route cyber, bio/chem and distillation queries to Opus 4.8.
A tier above Opus for long-horizon agentic work, with 1M context, 128K output, always-on adaptive thinking and raw chain of thought never returned. Same underlying model as Mythos 5, shipped with safety classifiers that fall back to Opus 4.8 (under 5% of sessions). Introduces mandatory 30-day retention for business traffic on Mythos-class models.
- Date
- Tuesday, 9 June 2026
- Lab
- Anthropic
- Kind
- model
- Access
- closed API
- Price
- $10/$50 per M tokens in/out; cache reads $1.00 per M until Fable 5.1 cut them to $0.25 (2026-06-09)
Figures
| Measure | Value | Measured by |
|---|---|---|
| Price per million tokens | $10 in / $50 out less than half of Mythos Preview's price | company |
| Sessions hitting safeguard fallback | under 5% average; classifiers tuned conservatively | company |
| Slay the Spire gain from file memory | 3x the improvement seen with Opus 4.8 also reached the final act 3x as often | company |
| Universal jailbreaks found in external bug bounty | none in 1,000+ hours UK AISI made progress toward one in a brief early window | company |
The name 'Fable' (Latin fabula) is paired with 'Mythos' to distinguish the safeguarded and unsafeguarded variants of one model. Included in Pro/Max/Team/seat-Enterprise plans only through 2026-06-22, then usage credits. A US export-control directive suspended it on 2026-06-12 (see anthropic-fable-5-export-control-suspension). InfoQ reports Microsoft pulled it from its internal Copilot model picker on 2026-06-10 over the 30-day retention rule (reported). Anthropic's benchmark table is an image, and Anthropic says it leads on nearly all tested benchmarks (company claim).
Sources
- www.anthropic.com/news/claude-fable-5-mythos-5
- platform.claude.com/docs/en/models/fable-5/introducing-claude-fable-5-and-claude-mythos-5
- www.infoq.com/news/2026/06/claude-5-release/
This record was checked against its sources on 6 October 2026. How we check