AWS Bedrock to require sharing data with Anthropic for Mythos and future models
Your data just left AWS's security boundary. Anthropic now requires 30-day retention on Mythos-class models—here's what that means for your enterprise.
Why it matters
AWS Bedrock users deploying Anthropic's highest-capability models (Mythos/Fable 5+) must now accept mandatory data retention and cross-boundary data sharing for safety monitoring. This marks a significant shift in enterprise AI deployment trade-offs: capability access vs. data sovereignty and security posture.
The key facts
6 to know30-day mandatory data retention required for Mythos and Fable 5 models on Bedrock
User data leaves AWS security and data boundary during retention period
Data deleted after 30 days except for safety investigations or legal holds
Policy applies to Mythos-class and future higher-capability models
Anthropic justifies retention for misuse pattern detection across multiple exchanges
Policy change announced June 2026 with low initial engagement (6 HN points, 0 comments suggests emerging awareness)
Go to the source
Hacker Newsnews.ycombinator.com
Publisher excerpt: > For Fable 5, Mythos 5, and future models on Bedrock with similar or higher capability levels, Anthropic will require 30-day retention for all traffic on Mythos-class models. Retaining data for a limited period allows Anthropic to detect patterns of misuse that are not visible from a single…