Microsoft has restricted internal employee use of Claude Fable 5, citing concerns over Anthropic's new data retention policies attached to the model. The move comes despite Microsoft rapidly deploying the model to GitHub Copilot and Azure AI Foundry customers externally. The situation highlights growing tension between commercial AI adoption and internal compliance standards at major tech firms, where third-party data retention terms can block internal use even when a product is actively sold to customers.
Anthropic says Mythos-class models require limited prompt and output retention for trust and safety work across platforms where they are offered. The policy took effect on June 9, 2026 and mainly affects organizations using Zero Data Retention through Claude Console, Claude Code Enterprise, AWS Bedrock, Google Cloud Agent Platform, or Microsoft Foundry. Consumer Claude Free, Pro, and Max plans are unchanged, while Anthropic describes restricted human review and automatic deletion after 30 days.