Claude Fable 5.1 Replaces Fable 5 — Same Slot, Same Pricing

September 2, 2026

Claude Fable 5.1 is Anthropic's latest Mythos-class model in the selector. It takes the seat Fable 5 held, at the same pricing. Existing Fable 5 conversations continue on 5.1 automatically. It still does not support zero data retention — using it is always an explicit pick.

What you can do

• Pick Claude Fable 5.1 from the model selector on any plan that could already reach Fable 5. It sits in Closed SOTA, where Fable 5 sat. The Auto router will never route you to it.
• Keep working in an existing Fable 5 thread — the next turn runs on 5.1. You do not re-pin.
• Use the same long-horizon shape — adaptive thinking (always on), effort high, 1M context, 128K max output, and tools.
• Pay the same as Fable 5 — Fable 5.1 replaces Fable 5 at the same pricing.

Where this shows up

You left a Fable 5 analysis open overnight. Open it this morning and keep going — the picker now says Claude Fable 5.1, and the work continues in the same thread.

You want one more pass after Opus 5, from Anthropic's latest Mythos-class model. Pick Claude Fable 5.1. It does not support zero data retention: inputs and outputs may be retained for safety review, so keep client-confidential material off this model.

You open a new chat and see the landing strip. It names Fable 5.1 and the retention caveat. Clicking it opens the picker on Closed SOTA, already on the list that holds the model.

Try it

• "Switch this conversation to Claude Fable 5.1 and continue the analysis from where we left off."
• "Use Claude Fable 5.1 to find the root cause of this rare crash — disassemble if you need to."
• "Plan a multi-day implementation of this design on Fable 5.1, with tests and a visual walkthrough as you go."

Heads up

• Not private. Fable 5.1 does not support zero data retention. Do not send client-confidential material, personal data, or anything you could not afford a third party to see.
• Removed from Auto and Swarm for the same reason as Fable 5. Using it is always an explicit pick.
• Fable 5 is retired. Sessions pinned to it roll forward to 5.1. Historical usage rows stay billed as Fable 5.
• No EU inference profile. EU Data Residency does not get a dedicated EU Fable 5.1 route; requests use the global Bedrock profile.