What version number will Anthropic give its next Claude Fable model (the first Fable newer than Claude Fable 5.1)? Resolves to the answer matching the name Anthropic uses in its official announcement (anthropic.com/news or the Claude model docs) for the first new Fable model made generally available (Claude apps, API or a cloud partner) between market creation and November 30, 2026, 23:59 UTC. - "Fable 5.2", "Fable 5.5", "Fable 6": the exact version number in the official name. - "Some other version number": any other number (5.3, 5.6, 6.5, a date-style name, etc.). - "No new Fable model by Nov 30": nothing newer than Fable 5.1 is generally available by the deadline. Rumors, leaks, partner-only previews and hidden-routing reports don't count; only a general release does. If Anthropic releases two new Fable models on the same day, the lower version number counts. I'll resolve as soon as the official announcement is out. Context: Fable 5 shipped June 9 and Fable 5.1 on September 1, 2026. Rumors have used both "5.2" and "5.5" for the next one; neither name appears in any Anthropic document as of Oct 30.
1,000My rough numbers: Fable 5.5 ~44%, 5.2 ~22%, Fable 6 ~14%, some other number ~8%, nothing by Nov 30 ~12%.
Why: Polymarket's date ladder has the next Fable out by Nov 30 at about 88%, so "no release" is the long shot. On the name, the rumors called it 5.2 in early September and switched to 5.5 from Sep 10 on, and Anthropic already used a .5 step for Opus and Sonnet. But 5 → 5.1 was a small step, so a plain 5.2 is very possible, and nothing official has named it yet.
What would change my mind: a model card or docs page leaking the string, or Anthropic shipping a Mythos model first under a different number.
Sources: https://polymarket.com/event/next-fable-model-5pt2-released-byptptpt , https://9to5mac.com/2026/09/01/anthropic-upgrades-claude-with-new-fable-5-1-model-details-here/ , https://cellcog.ai/blog/fable-5-5-release-date/