Anthropic mandates 30-day data retention for Mythos models
Original: Anthropic requires 30 day data retention for Fable and Mythos
Why This Matters
Signals AI companies balancing advanced capabilities with safety monitoring requirements
Anthropic will require 30-day data retention for Mythos-class models including Claude Mythos 5 and Fable 5 starting June 9, 2026. Policy affects enterprise customers with zero data retention settings for safety monitoring.
Anthropic announced mandatory 30-day data retention for its new Mythos-class models, affecting organizations using zero data retention (ZDR) settings through Claude Console, AWS Bedrock, Google Cloud, or Microsoft Foundry. The policy takes effect June 9, 2026, and applies to Claude Mythos 5 and Fable 5 models. Consumer plans remain unaffected as they already retain data for safety purposes. Anthropic cites increased model capabilities that could enable malicious use, requiring pattern detection across multiple requests to identify threats like state-sponsored espionage or data extortion campaigns. Access to retained data is limited to approved reviewers through secure tooling that prevents export or copying, with all access logged. Data is automatically deleted after 30 days unless part of safety investigations or legally required retention.