Microsoft is changing how it charges for its software for the first time in two decades, moving to bill customers with a pay-as-you-go model each time they use its new AI agent. The change, prompted by the soaring cost of artificial intelligence, came Tuesday as the company launched Copilot Cowork — an AI “agent” that can independently carry out office tasks like drafting documents, building spreadsheets and sending emails. The tool still requires a paid Microsoft 365 Copilot subscription, but now every task it runs is billed separately, based on how much computing power it consumes.