Fable 5.1, Now Live in :Harvey:

Claude Fable 5.1, the latest Anthropic model, is now available. Starting today, Harvey customers can opt-in to receive access.

In our early testing, Fable 5.1 was strongest on complex, document-heavy analysis, with the most significant quality improvement on litigation and dispute resolution compared to Fable 5. Generally, Fable 5.1 also performed well across tasks related to data privacy and cybersecurity and capital markets.

Notably, Fable 5.1 also delivers quality results even at lower reasoning levels. At its lowest reasoning setting, Fable 5.1 was thorough in completing tasks, while using roughly half the output tokens. Balancing quality and overall efficiency is meaningful, especially for legal teams working through high-volume work, such as reviewing agreements.

For full results against our Legal Agent Benchmark, you can refer to the public leaderboards on Artificial Analysis and Vals.

What to Know Before Enabling Fable 5.1

The use of Fable models, including Fable 5.1 and Fable 5, may involve data processing practices that differ from data commitments we made in our existing customer agreements. Eligible Harvey customers can use Fable 5 and Fable 5.1 with zero data retention under a time-bound exemption while Anthropic rolls out Enterprise Frontier Safeguards. Enterprise Frontier Safeguards will give eligible customers the ability to deploy Anthropic's most capable models while storing their data in cloud infrastructure controlled by Harvey or by the customer.

Note Anthropic does not offer any regional processing for Fable 5.1 or Fable 5, so all data will be processed in the United States.

We are making this model available as an opt-in option vs. by default. Our goal is to give customers access to a highly capable model while preserving their ability to decide what’s right for their organization.

Customers who have opted in to Fable 5 will get Fable 5.1 access in Harvey starting this week.

If you have questions or are interested in enabling Fable models for your organization, please reach out to your account team.