Copilot API for usage

Microsoft now exposes prompt counts through the Microsoft 365 Copilot usage reports API in Microsoft Graph. Call the v1.0 Copilot usage-user-detail report with report version 2 and a supported period such as D7, D28, D90, D180, or ALL, using Reports.Read.All. Its streamed CSV includes user identity, last-activity dates, prompts submitted for all apps, Copilot Chat work and web prompt counts, and active usage days, without exposing prompt content. The limitation is licensing: Graph returns usage only for users assigned a Microsoft 365 Copilot license. Unlicensed Copilot Chat usage remains available in the admin-center report, not Graph reports. Save the report refresh date, compare several periods, and require sustained inactivity before reclaiming a license. Exclude newly licensed users, people on leave, and service accounts, then have an owner review proposed removals. This prevents revoking access because of reporting delay or a short quiet period