A new model identifier, azure_ai/claude-fable-5-5, appeared in LiteLLM's model data on October 13, sourced from an Azure Models API listing for the East US 2 region. The listing marks the model as generally available with a December 2027 deprecation date, but nearly every other field is inherited from Fable 5.1, and no source yet states a price, capability or context figure specific to Fable 5.5.

A tipster cited by Wccftech said Fable 5.5 is slated to land this week, possibly as soon as today, barring late hold-ups. Separate chatter claimed a quiet grey-scale test in the Claude web interface, but those reports are anecdotal and unverified.

Treat this as rumor-grade for now. Anthropic's own documentation, pricing pages and newsroom still list Fable 5.1 as the newest Fable model, with Haiku 5.5 on October 7 as its most recent model announcement, and independent trackers have no Fable 5.5 page. An infrastructure listing is a classic pre-launch tell, not a launch.

Update October 16: a leaker account, Lyra, claimed on October 15 that partner companies have received Fable 5.5 for testing and guessed at a launch next week, while stressing there was no release date. Separately, the LiteLLM listing that started this rumor had been removed by October 16. Anthropic has still announced nothing, and Fable 5.1 remains its newest Fable model, so this stays unresolved.

Update October 17: TestingCatalog reported that Fable 5.5 has reportedly reached Anthropic's partners, with six early-access codenames spotted in the Devin CLI, plus one in a GitHub model picker, suggesting it may not be the only model on the way; the codename Onigiri is tipped as the favourite for Fable 5.5. Anthropic has confirmed nothing, and a launch next week is presented as plausible, not scheduled, so this stays unresolved.