By No Code MBA · Facts checked
- Provider
- Anthropic
- Announcement date
- Status at last check
- Generally available
- Model family
- Claude Fable
- Preceding model
- Claude Fable 5
- Capabilities
- Text, Image, Coding
What changed
Fable 5.1 is Anthropic's update to Fable 5 for coding, knowledge work and long-running agent tasks, including multi-day sessions, writing its own tests and checking its work with vision. Cache reads cost 75% less than Fable 5, which Anthropic estimates saves about 25% on typical workloads and up to about 45% on highly agentic ones. Customers quoted by Anthropic, including Jane Street and Cognition, report solving more internal coding problems or matching Fable 5 at lower cost per task.
Access and availability
Available on Claude Pro, Max, Team and Enterprise plans and through the Claude Platform API as claude-fable-5-1, plus Amazon Web Services, Google Cloud and Microsoft Foundry. US-only inference is offered at 1.1 times standard pricing.
Official access documentationPricing
$10 per million input tokens, $50 per million output tokens and $0.25 per million cache-read tokens; US-only inference is 1.1 times the input and output prices.
Official pricingWhat you can build
Try an end-to-end feature brief: ask it to inspect your app, implement the change, write checks, and explain the result.
Read our Fable 5.1 reviewLimitations
Cybersecurity, biology and chemistry safeguards block or reroute some requests to less capable models (Opus 4.8 for cyber, Opus 5 for biology), and API customers must configure the Fallback API. Data is retained 30 days by default for safety monitoring, and Anthropic does not state the context window size.