Anthropic has launched its hyper-advanced Claude Fable 5 and Mythos 5 models, instantly expanding the AI capabilities of cloud giants Amazon Web Services and Microsoft Foundry.
- Anthropic PBC is releasing Fable 5, a version of Mythos with guardrails that prevent it from responding to cybersecurity queries.
- Claude Fable 5 for general public commercial use and will reroute dangerous queries to Claude Opus 4.8 and Claude Mythos 5.
- Amazon Web Services and Microsoft have integrated Fable 5 into their ecosystems to power the next era of enterprise-grade autonomous software agents.
Artificial intelligence startup Anthropic PBC on Tuesday announced the commercial launch of Claude Fable 5 and Claude Mythos 5, debut models in its next-generation "Mythos-class" architecture that significantly outperform previous systems at executing complex, multi-day tasks.

The Claude AI maker stated that Fable 5 marks its most capable model to date, leading frontier benchmarks in software engineering, vision processing, and scientific research. In early corporate deployments, the model demonstrated the ability to execute long-horizon autonomous workflows.
Fable 5 and Mythos 5 Details
Claude Fable 5 will be accessible to the general corporate market but includes strict, conservative safety classifiers designed to prevent the model from being leveraged for harmful operations. According to the company, if a user prompt triggers risk thresholds in sensitive fields like biochemistry or weapon systems, the query is seamlessly rerouted to Anthropic's next-most-capable model, Claude Opus 4.8.
Concurrently, Anthropic released Claude Mythos 5, an identical underlying model that operates without general safety restrictions. Access to Mythos 5 is highly restricted, initially deployed through "Project Glasswing" in exclusive collaboration with the United States government and vetted critical infrastructure defenders to actively uncover software vulnerabilities and accelerate therapeutic drug designs. The model will be made available to only those who are a part of Project Glasswing.
Amazon Includes Fable 5 on Amazon Bedrock, AWS
Amazon announced the availability of Claude Fable 5 on Amazon Bedrock and the Claude Platform on AWS.
"Claude Fable 5 makes Mythos-level capabilities available to all customers, with strong safeguards designed to make it safe for broader use. Fable 5 is state-of-the-art on nearly all tested benchmarks and delivers exceptional performance in software engineering, knowledge work tasks, and vision - built for ambitious, long running work," the company explained.
"With Claude Fable 5 on Bedrock, you can build within your existing AWS environment and scale inference workloads. You can also use Claude Fable 5 through the Claude Platform on AWS, giving you Anthropic's native platform experience,” Amazon said in a press release.
Fable 5 Also Available On Microsoft Foundry
Microsoft Corp. simultaneously expanded its frontier AI lineup by onboarding Claude Fable 5 into Microsoft Foundry, its dedicated environment for complex, autonomous operational workflows.
This elevated level of autonomy changes what teams can ask AI to do. Enterprises can now delegate sophisticated multi-turn projects to agents, enabling them to reason over your organization's data to solve real problems, Microsoft said in a press statement.
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