Claude Fable 5 at a glance
Anthropic released Fable 5, a generally available Mythos-class model, and Mythos 5, the same model with looser safeguards for vetted defenders; access was briefly suspended after US export controls.
What changed with Claude Fable 5
Claude Fable 5 and Claude Mythos 5 share one underlying model. Fable 5 is the general-use version; Mythos 5 lifts some safeguards and was offered first to a small group of cyber defenders and infrastructure providers. Both are priced at $10 input and $50 output per million tokens, and the API release notes list a 1M-token context window.
Fable 5 uses classifiers for cybersecurity, biology and chemistry, and distillation. When one triggers, the reply is handed to Claude Opus 4.8 and the user is told. Anthropic said this happens in under 5% of sessions on average.
On June 12 the US government applied export controls to both models, and Anthropic suspended access for all users. After the controls were lifted and a stronger classifier was trained, Fable 5 returned on July 1.
Claude Fable 5 benchmarks and pricing
Values are copied from the linked source on the date shown. They are not IA Compa measurements.
- Input price per 1M tokensas of · Source for Input price per 1M tokens: anthropic.com (opens in a new tab)
- $10.00
- Output price per 1M tokensas of · Source for Output price per 1M tokens: anthropic.com (opens in a new tab)
- $50.00
- Context windowas of · Source for Context window: platform.claude.com (opens in a new tab)
- 1M tokens
How it compares
Other models in the same category that we have covered, using each model's latest recorded value. (Models)
Where to compare Claude Fable 5
Independent leaderboards and official resources for comparing this model yourself. Rankings change often; each site shows its own current data.
Leaderboards
General leaderboards
Official resources
Why Claude Fable 5 matters for businesses
For businesses, the episode shows that frontier models can face sudden availability changes. Production workflows should keep a fallback model and handle refusals or reroutes cleanly.
Sources for this story
- Claude Fable 5 and Claude Mythos 5 (opens in a new tab)Official
Anthropic · anthropic.com
- Redeploying Claude Fable 5 (opens in a new tab)Official
Anthropic · anthropic.com
- Claude Platform release notes (opens in a new tab)Official
Anthropic · platform.claude.com
Last verified: . IA Compa summarizes public announcements for business readers. We are not affiliated with the companies mentioned. Always confirm details, pricing, and availability with the official source.
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- #anthropic
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- #safety
- #cybersecurity
