Claude Fable 5.1

Name: Claude Fable 5.1
Price: 10 USD
Author: Anthropic

✅ Active

Anthropic's most capable generally available model, a Mythos-class model with safeguards for the most demanding reasoning and long-horizon agentic work

Provider list prices

Context Window

Input Price

$10.00/1M

Output Price

$50.00/1M

Released

Sep 1, 2026

Capabilities

textvisionextended-thinkingtool-usecode

Crazyrouter API catalogue

Not confirmed in the current default-group API catalogue.

Catalogue checked: 2026-10-10T14:22:39+00:00. USD per 1M tokens, default group. The first context tier is shown; long contexts may cost more. This is a gateway catalogue snapshot, not a provider release announcement.

Get API Access →Current API models

Version History

Sep 1, 2026New Release

Claude Fable 5.1 released alongside the restricted-access Claude Mythos 5.1, with a 1M context window, 128K max output, always-on adaptive thinking, and a June 2026 knowledge cutoff

Sep 1, 2026Pricing Change

Pricing unchanged from Fable 5 at $10.00 per 1M input tokens and $50.00 per 1M output tokens; cache reads cut 75% from $1.00 to $0.25 per 1M tokens

Sep 1, 2026Update

Forced tool use behavior changed (breaking change); Anthropic recommends starting workloads on Opus and escalating to Fable 5.1