Claude Fable 5.1 from Anthropic is now available on AWS

Update: This article was originally published on June 9, 2026, and updated September 1, 2026. It has been updated to reflect the availability of Claude Fable 5.1.

Key takeaways

Claude Fable 5.1 achieves clear gains over Fable 5 on benchmarks.
Powers agents across the software lifecycle including codebase-wide features, code review, and performance work.
Scientific research is supported across the full cycle, with formal verification to check its own reasoning.

Claude Fable 5.1 is now available on Amazon Bedrock and Claude Platform on AWS. Fable 5.1 is built to run demanding work end to end across software, documents, and research. It outperforms Claude Fable 5 on Anthropic's most difficult evaluations and is built for long-running, high-stakes tasks that engineering teams, analysts, and power users depend on daily. Because those capabilities create elevated risk if misused, Anthropic has designated it a Covered Model—a category that carries additional data retention, safety review, and access policies.

Anthropic also announced Enterprise Frontier Safeguards, a solution that will give customers the option to safely deploy Anthropic's most capable models while keeping their data in cloud infrastructure they control.

Claude Fable 5.1 shows improvement in the following areas

According to Anthropic, the new model represents a step-change in what customers can accomplish with AI. Here's what sets it apart:

Stronger reasoning—Improves on the previous generation on the hardest math, science, and multi-step benchmarks — better judgment, fewer confident wrong answers.
Agentic coding—Handles larger engineering work across multi-hour sessions and reports honestly, flagging blockers instead of faking success.
Autonomous operation—Built for multi-hour jobs that span many applications. It plans, uses the tools it needs, recovers when a step fails, and keeps you updated without being asked.
End-to-end knowledge work—Takes an analysis from question to finished deliverable, including its best-yet Excel and PowerPoint, for finance, accounting, and healthcare teams.
Scientific research—Runs full research campaigns across disciplines, from literature and hypotheses to models, experiments, and formal verification.
Improved usability—Clearer writing, better instruction-following, and steady updates on long-running tasks.

How to access Claude Fable 5.1 on AWS

Customers can get started with Claude Fable 5.1 through Amazon Bedrock or Claude Platform on AWS:

Amazon Bedrock: Build within your existing AWS environment and scale inference workloads. Access the model programmatically using the Anthropic Messages API, the Invoke and Converse APIs via the AWS CLI and AWS SDK, or use it in the Bedrock console Playground. Access requires opting into data retention through the Data Retention API.
Claude Platform on AWS: Access through Anthropic's native platform experience, available in North America, South America.

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