WinUI 3

Purpose

Build modern Windows desktop applications using WinUI 3 with the Windows App SDK — Microsoft's native Windows UI framework with Fluent Design, Mica materials, and access to WinRT APIs without UWP constraints.

Agent Protocol

Trigger

Exact user phrases: "WinUI 3", "Windows App SDK", "WinUI XAML", "Fluent Design", "Mica", "WinUI desktop", "WinUI navigation", "NavigationView", "InfoBar", "WinUI 3 app".

Input Context

• Windows App SDK version (1.3, 1.4, 1.5+)
• .NET version (.NET 6+ for C#, or C++/WinRT)
• App packaging (MSIX packaged, unpackaged, or both)
• UI requirements (NavigationView, TabView, DataGrid, custom controls)
• OS features needed (notifications, background tasks, Share, Mica)
• Deployment strategy (Store, sideloading, enterprise MSI)