For the hardest coding and agent work where cost matters less; $10/$50 per million tokens, though cheaper cache reads soften long runs.

Kenning's take

What it does

Claude Fable 5.1 is the generally available version of the same model as Claude Mythos 5.1, with extra safeguards for cybersecurity and biology. Anthropic calls them its most advanced models for coding and knowledge work. Cache reads cost 75% less than on Fable 5, which Anthropic says cuts typical costs by about 25%.

• Anthropic's strongest general-access model at launch
• Cache reads at $0.25 per million tokens
• Same base model as Claude Mythos 5.1
• Available on all major cloud platforms
• 1 million token context window

Who it suits. Developers and paid Claude users running long, complex agent and coding work.

Key facts

Category

AI models

Part of

Claude

Made by

Anthropic

Based in

United States

Released

1 September 2026

How to get it

in the API as claude-fable-5-1 and on AWS, Google Cloud and Microsoft Azure; in Claude, on paid plans through usage credits or a share of weekly limits (not on Free)

Works on

Web, iOS, Android, macOS, Windows, API

In the UK

Yes

API price

$10 per million input tokens, $50 per million output tokens; cache reads $0.25

Reviews and write-ups

• SD Times 2026-09-02

FAQ

Facts from the maker's own pages and the sources listed. Checked 2026-10-11.