Anthropic mandates 30-day data retention for Claude Mythos 5 and Fable 5
Zero retention workspaces must now keep prompts and outputs for 30 days.
Anthropic announced a new data retention policy for its most advanced models, Claude Mythos 5 and Claude Fable 5, which share the same underlying architecture but differ in safety guardrails (Fable adds cyber and bio protections). Starting June 9, 2026, any organization using zero data retention (ZDR) workspaces on Claude Console, Claude Enterprise, AWS Bedrock, Google Cloud Agent Platform, or Microsoft Foundry must retain prompts and outputs for 30 days. This change does not affect consumer plans (Free, Pro, Max) or organizations that already retain data.
The rationale is to detect large-scale misuse patterns, such as Best-of-N jailbreaking (sending hundreds of prompt variations) or state-sponsored espionage, which only become visible when analyzing multiple requests together. Anthropic emphasizes that employee access is tightly controlled: only a small team can review flagged data through tools that prevent copying or export, and all access is logged in tamper-proof records. Organizations can optionally add customer-managed encryption keys and audit logs. After 30 days, data is deleted unless part of an ongoing safety investigation or legal requirement.
- Policy applies exclusively to organizations with zero data retention (ZDR) on Anthropic, AWS, Google Cloud, or Microsoft platforms; consumer plans are exempt.
- Data is retained for 30 days, automatically deleted, and accessible only by a small review team for safety or legal reasons.
- Customer-managed encryption keys and audit logs are available for eligible organizations to maintain control.
Why It Matters
Enterprise users of top-tier AI models must balance safety oversight with data privacy—a growing tension in responsible deployment.