By Reuters
Publication Date: 2026-06-10 17:48:00
June 10 (Reuters) – Microsoft is limiting employees’ use of Anthropic’s Claude Fable 5 because of the AI startup’s new data retention requirements, The Verge reported on Wednesday, citing sources.
Anthropic on Tuesday said it is rolling out Claude Fable 5, a public version of its Mythos AI model, with guardrails barring its use in risky areas such as cybersecurity.
Claude Fable 5 is the most powerful model Anthropic has made available for wider use, with the company citing its performance in software engineering and analytics.
Microsoft has told employees that its legal teams are evaluating changes to Anthropic’s data retention requirements, according to the report.
The concerns center on customer data and confidential information, and it is not yet clear whether Microsoft’s legal teams will clear Claude Fable 5 for internal use, the report said.
Under Anthropic’s data retention policy for Mythos-class models, prompts submitted and…