$0.0994 per vCPU-hour. That is what the sandbox will cost, the one where Microsoft runs your agent, once billing starts on December 1, 2026.
Fact
The facts: on October 28, 2026 Microsoft introduced the Copilot harness in Foundry Agent Service - in its words a fully managed way to build agents that reason, use tools and complete complex, long-running tasks. The harness is in public preview. Microsoft runs the agent loop and the sandbox, and the customer supplies the knowledge, procedures and tools. The model is picked from those supported in Foundry; the page does not name them, or say which regions it runs in. Durability for hosted agents on long tasks is generally available starting this week. Microsoft writes that billing for the harness begins December 1, 2026, with consumption-based pricing. Until then the harness time is free; models and separately billed tools are paid at their own prices. From December 1 the sandbox costs $0.0994 per vCPU-hour and $0.0118 per GiB per hour, according to Microsoft, and prices may vary by region and agreement.
The harness is everything around the model: the loop that makes it think, call tools and finish the task, and the sandbox it works in. Until now you built it yourself. Here Microsoft offers it as a service.
To be clear: this is not Copilot for everyone. It is a service for developers in Foundry, in public preview.
The wrapper around the model becomes a product for rent, by the processor-hour.
The money comes in two steps. Until December 1 the harness is not billed, while models and tools already are. From December 1 you add the sandbox, by the hour. How many hours one long task burns, Microsoft does not say.
Before December 1, run one long task and note how many hours and how many vCPUs it eats. That way you know the bill before it arrives.
Official primary sources
Microsoft Foundry blog - Microsoft Copilot harness in Foundry, 28.10.2026The visual is generated code-art, no third-party images.