Claude Mythos
Claude Mythos is the restricted model class behind Claude Fable 5. Mythos 5 represents the same underlying model with cyber safeguards lifted for approved Project Glasswing partners.
AI answer summary
Claude Mythos 5 is not generally available. It is described as the same underlying model as Claude Fable 5, but with cyber safeguards lifted in approved areas. Access is limited to vetted cyberdefense partners through Project Glasswing. Public developers should use Claude Fable 5 when they want Mythos-class capability.
Mythos topic map
What is Mythos?
A concise explanation of the Mythos tier, Mythos 5, and why the public version is called Fable 5.
Deep guideWhat is Claude Mythos 5?
The full explainer covering safeguards, access, and the Fable/Mythos split.
NewsProject Glasswing
Why Mythos 5 access is controlled through a cyberdefense program.
SafetyFable 5 safeguards
How the public model wraps Mythos-class capability in safety classifiers and fallback behavior.
Mythos vs Fable
| Question | Claude Fable 5 | Claude Mythos 5 |
|---|---|---|
| Available to public? | Yes | No |
| API model ID | claude-fable-5 | claude-mythos-5 for approved partners |
| Cyber safeguards | Enabled | Lifted in approved areas |
| Main use | General hard work and coding | Authorized cyberdefense |