Microsoft rolls out Claude Fable 5.1 in Copilot Cowork and Copilot Studio

Microsoft is rolling out Anthropic's Claude Fable 5.1 in Copilot Cowork and Copilot Studio, adding the long-horizon model to the frontier options eligible customers can use as they delegate more complex work to AI. Work IQ grounds the model in a user's files, meetings, chats, and business data—within existing permissions—so it can reason over workplace context rather than the prompt alone, with sources that can be traced back to that work.