Microsoft's WinUI Agent Plugin Cuts Token Usage by 70% for Developers

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Native Windows App Development Gets Boost from New WinUI Agent Plugin

Microsoft has released a plugin that significantly streamlines the process of developing native Windows apps using WinUI 3.

The plugin, dubbed “winui-dev,” loads two primary skills out of the box:
“winui-dev-workflow” handles project creation, building, and error diagnosis;
“winui-design” covers XAML layout, control selection, theming, and accessibility.

According to Microsoft, the plugin reduces the number of tokens required for development by over 70% through optimized architecture and reliance on existing tools.

Additional skills are available to assist with code review, UI testing, MSIX packaging, WPF-to-WinUI migration, environment setup, and session diagnostics. These skills were designed to operate independently without interference, ensuring seamless composition and minimizing potential conflicts.

Accompanying Tools

“winui3-analyzer” is a Roslyn analyzer injected at build time to identify common WinUI 3 pitfalls, including UWP namespace leaks and missing EnsureCoreWebView2Async calls.
“winui-search” indexes WinUI Gallery and Community Toolkit samples, enabling the agent to query real control patterns before writing XAML.
“winmd-cli” provides offline API metadata lookup against .winmd and managed.dll files, allowing the agent to verify API existence before generating code.

Plugin Availability and Feedback

The plugin is available now for GitHub Copilot CLI via the awesome-copilot registry. Microsoft is soliciting feedback through the associated GitHub repository.