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ReleaseVerified

September 1, 2026

September 1, 2026 Claude Fable 5.1 and Claude Mythos 5.1 launch We just launched Claude Fable 5.1 and Claude Mythos 5.1, the world’s most advanced models for coding and knowledge work. For more information, see our blog post: Claude Fable 5.1 and Mythos 5.1 .

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Evidence chain

Anthropic Claude Apps release notesOfficial · official

September 1, 2026 Claude Fable 5.1 and Claude Mythos 5.1 launch We just launched Claude Fable 5.1 and Claude Mythos 5.1, the world’s most advanced models for coding and knowledge work. For more information, see our blog post: Claude Fable 5.1 and Mythos 5.1 .

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External discussion

No reviewed external discussion has been linked yet. This does not change the evidence confidence.