Microsoft has made Copilot Cowork generally available worldwide, rolling out an agentic tool that carries out complex, long-running work across a user's Microsoft 365 setup. The tool does what its name suggests. Cowork sends emails through Outlook, builds Word and Excel files, schedules meetings, and posts in Teams, with users approving sensitive actions before each one happens.
How Cowork Works
Cowork breaks a request into steps and works through them one by one, showing each step in the conversation as it goes. It can run deep research across an organisation's files, reorganise folders in SharePoint and OneDrive, and run prompts on a schedule so recurring tasks happen on their own.
Adoption by Fortune 500
Accenture, Koch, and half the Fortune 500 already signed on Microsoft's Cowork during the preview. The numbers Microsoft is putting forward are aimed at signalling momentum. After three months in its Frontier preview program, more than half of the Fortune 500 were using Cowork, alongside names like Accenture, Capital Group, Koch, and Zurich Insurance. Microsoft called it the fastest-growing feature in the history of its Frontier program.
Use Cases
The use cases hint at the appeal. One engineering team taught Cowork to safely edit batch-job spreadsheets and draw dependency flowcharts after every change. Another compared nearly 4,000 files across two product versions, work Microsoft says would have stretched into weeks. A sales lead pointed it at a stalled pipeline and got back a ranked list of at-risk deals with the exact follow-up that had gone quiet on each.
What Copilot Cowork Actually Costs to Run
Cowork runs on a usage-based model that may take some getting used to. It needs the Microsoft 365 Copilot User Subscription License, then bills separately in Copilot Credits priced at $0.01 each under the pay-as-you-go option. Each task's cost depends on four things: model use, context retrieval, tool calls, and runtime.
Cost Controls
Because that pricing is variable, Microsoft is shipping cost controls alongside it. Cowork is off by default, admins can set spending limits at tenant, group, and user levels, and usage alerts can flag when budgets get crossed.
Model Options
At launch, Cowork runs on Anthropic's Opus 4.8 and Sonnet 4.6, with GPT 5.5 available in Frontier. A fine-tuned in-house model, Cowork 1, is due in the coming weeks, built to handle everyday tasks at lower cost. Microsoft also claimed its internal testing showed Cowork was 30 to 40 percent cheaper per prompt than Anthropic's rival Claude Cowork. Billing starts now, though Frontier participants get a grace period until July 1.
