Fable 5 and Mythos 5 suspended under US export controls
A US export-control directive forced Anthropic to suspend Fable 5 and Mythos 5 for all users on 2026-06-12; access returned 2026-07-01.
The directive barred all foreign-national access; with no way to verify nationality in real time, Anthropic switched both models off globally. The trigger was an Amazon report of a safeguard bypass. The fix was a retrained classifier that blocks that technique in over 99% of cases and a wider safety margin, plus a draft industry jailbreak-severity framework.
- Date
- Friday, 12 June 2026
- Lab
- Anthropic
- Kind
- infra
- Access
- closed API
Figures
| Measure | Value | Measured by |
|---|---|---|
| Outage length | 19 days 2026-06-12 to 2026-07-01 for Fable 5; Mythos 5 returned for US organizations only | company |
| Reported bypass blocked after retraining | over 99% of cases specific Amazon-reported technique; CAISI also tested the safeguards | company |
Anthropic disagreed with the action and says the government gave no specific details of its national-security concern; its tests found 8 other models (including Opus 4.8, GPT-5.5 and Kimi K2.7) could produce the same demonstration. InfoQ quotes White House AI adviser David Sacks hoping for remediation and a lifted control (reported). Controls lifted 2026-06-30; the public statement is dated 2026-06-30 and 2026-07-01.
Sources
- www.anthropic.com/news/redeploying-fable-5
- www.anthropic.com/news/fable-mythos-access
- www.infoq.com/news/2026/06/claude-5-release/
This record was checked against its sources on 6 October 2026. How we check