Microsoft is not the only company ‘warning’ about using Anthropic Claude Fable, other companies too are worried that…

When Anthropic flipped the switch on Claude Fable 5—its first publicly available Mythos-class model— on June 9, the AI giant quietly rewrote a clause enterprises had been counting on. Every prompt and every output now sits on Anthropic’s servers for 30 days. No opt-out. No Zero Data Retention carve-out, even for the enterprise customers who had specifically negotiated one. Microsoft was the first big name to flinch—but it isn’t the only one.

The Verge first reported this week that Microsoft has restricted Claude Fable 5 from the internal model picker its employees use inside GitHub Copilot, even as the company rolled out the same model to its Copilot and Foundry customers.