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20262020s
Claude Fable 5
Anthropic released Claude Fable 5 on June 9, 2026, its first Mythos-class model positioned a tier above the Opus line.
Why It Mattered
Fable 5 debuted a new 'Mythos' capability class above Opus, setting state-of-the-art results across coding and reasoning benchmarks. Days after launch, on June 15, Fable 5 and Mythos 5 were suspended under a US export-control directive — an unprecedented government intervention in a commercial frontier model's availability — before returning to full worldwide availability on July 1, 2026. The episode became a defining case study in how national-security policy now directly shapes frontier AI deployment.
Who Built It
Anthropic
Applications
- Frontier Reasoning
- Agentic Coding
- Research