Initial Release and Immediate Reactions
Anthropic introduced Claude Fable as its first Mythos-class AI model, and the launch quickly generated attention within Microsoft. Reports indicate that the company has moved to limit how its own staff can interact with the latest version due to shifts in data handling practices from Anthropic.
Access Limitations for Employees
Microsoft has rolled out Claude Fable 5 to GitHub Copilot and Foundry customers without delay. At the same time, the model does not appear in the internal model selection tools used by Microsoft employees for company versions of GitHub Copilot. Other Claude models remain accessible internally because they continue to follow established Zero Data Retention protocols.
Data Retention Policy Shifts
The core issue stems from Anthropic's updated data retention requirements that accompany the new model. These changes diverge from the stricter zero-retention standards Microsoft prefers for internal operations. As a result, decision makers at Microsoft have chosen to keep the model out of employee-facing environments while still supporting external users who may accept different terms.
