Reports circulating on X suggest that a new model, Claude Fable 5.5, has appeared in Microsoft Azure configuration files. As of October 13, 2026, neither Anthropic nor Microsoft has officially confirmed the existence or upcoming release of this model.
Anthropic’s official documentation currently identifies Fable 5.1, released on September 1, 2026, as the most advanced version in the Fable series. The original Fable 5 model launched on June 9, 2026, featuring a 1 million token context window and pricing of $10 per million input tokens and $50 per million output tokens.
While Anthropic has recently released other models in the 5.5 family, including Opus 5.5 on September 22, 2026, and a subsequent Sonnet 5.5, no Fable variant has been included in these announcements. The Fable 5.5 designation appears to be based on pattern-matching rather than official company statements.
Anthropic has released Fable 5, Fable 5.1, Opus 5.5, and Sonnet 5.5 within a period of approximately four months. Until official documentation or announcements from Anthropic, Microsoft, AWS, or Google Cloud confirm the new model, Fable 5.1 remains the flagship offering.
