Anthropic Claude Fable 5 on AWS: Mythos-class capabilities with built-in safeguards now available | Amazon Web Services

Claude Fable 5 is now available through Amazon Bedrock and Claude Platform on AWS, offering Mythos-level performance with safeguards for broader access. Anthropic highlights its ability to perform long-running tasks, analyze complex visual documents, and verify or improve its own work. Access requires specific data-sharing consent, and higher-risk requests may be routed to Claude Opus 4.8.

Capabilities and Safeguards

• Supports extended, asynchronous coding and knowledge-work tasks with minimal intervention.
• Interprets diagrams, charts, tables, files, and PDFs for research, finance, legal, analytics, architecture, gaming, and software development.
• Uses vision to compare implemented designs with intended goals.
• Can update skills, create evaluation harnesses, and perform proactive self-verification.
• Cybersecurity, biology, chemistry, and health prompts with elevated misuse risk may be handled by Opus 4.8 instead.
• The unrestricted Claude Mythos 5 is limited to a small group of vetted customers.

Accessing Fable 5 on Amazon Bedrock

• Available through:
  • Anthropic’s Messages API using bedrock-mantle or bedrock-runtime.
  • AWS Invoke and Converse APIs through bedrock-runtime.
  • The Amazon Bedrock console Playground.
• Model access is being expanded gradually across AWS accounts; customers can contact AWS Support for expedited access.

Required Data Sharing

• Users must opt into data sharing through the Data Retention API by setting provider_data_share.
• No console interface is available for this setting at launch.
• Anthropic requires:
  • 30-day retention of inputs and outputs.
  • Human review.
• Data retention enables abuse detection across multiple interactions rather than isolated requests.
• Example endpoints are provided for both bedrock-mantle and bedrock-runtime.

SDK and API Usage

• Install the Anthropic Python SDK with pip install anthropic.
• The Messages API can be called through the Bedrock Mantle endpoint using model ID anthropic.claude-fable-5.
• Boto3’s Converse API supports unified multi-model access through model ID global.anthropic.claude-fable-5.
• Users can configure token limits and submit tasks such as designing a multi-region AWS architecture supporting 100,000 requests per second.

Pricing and Routing

• Requests routed to Opus 4.8 because of harmful content are charged at Opus rates.
• If a conversation is blocked mid-request, initial tokens are charged at Fable rates and later tokens at Opus rates.
• Pricing details are available on the Amazon Bedrock pricing page.

Claude Fable 5 is best suited to ambitious, long-running workloads that benefit from advanced reasoning and document or visual understanding. Before using it, organizations should confirm account access, configure the required data-sharing settings, and evaluate whether the 30-day retention and human-review requirements fit their compliance policies.