Build or review WinUI 3 applications with the Windows App SDK, including MVVM patterns, packaging decisions, navigation, theming, windowing, and interop boundaries with other .NET stacks. USE FOR: building native modern Windows desktop UI on WinUI 3; integrating Windows App SDK features into a .NET app; deciding between WinUI, WPF, WinForms, and MAUI for Windows. DO NOT USE FOR: unrelated stacks; generic tasks that do not need this specific guidance. INVOKES: inspect the repository context, edit
SkillScore95Maintained
Automatic
◆Frontend / UI pack
Last verified 8/19/2026
What it changes
Passed 21 of 22 test cases with the skill, and 14 of 22 without it.
Without skill64%
With skill95%
Checks it passed that the model alone missed
The answer cites Windows App SDK version 1.8.11.
The XAML layout uses x:Bind for compiled data bindings.
The code uses ApplicationData.GetForUnpackaged() to access storage.
and 4 more in the full report
7 fixed14 passed either way1 still failing0 broke
Pass-rate lift
+32 pp
Tokens
+32%
Agent turns
0%
Response time
-29%
Model gemini-3.6-flashMeasured 8/19/2026v221 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 7 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 7
Prompt
We are planning an upgrade to Windows App SDK version 2.3.1. What feature was introduced in this release for schema-constrained local AI model output processing?
What was checked, without and with the skill
Checked
Without skill
With skill
The response identifies schema-constrained Phi Silica JSON output as a feature in 2.3.1.
Missed
Passed
case-11 · gemini-3.6-flash · 8/19/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md94 lines3 files
WinUI 3 and Windows App SDK
Trigger On
building native modern Windows desktop UI on WinUI 3
integrating Windows App SDK features into a .NET app
deciding between WinUI, WPF, WinForms, and MAUI for Windows work
implementing MVVM patterns in Windows App SDK applications
Workflow
Confirm WinUI is the right choice — use when modern Windows-native UI, Fluent Design, and Windows App SDK capabilities are needed. For cross-platform, consider MAUI instead.
Choose packaging model early — packaged (MSIX) vs unpackaged differ materially for deployment, identity, and API access:
<!-- Unpackaged: add to .csproj -->
<WindowsPackageType>None</WindowsPackageType>
Apply MVVM pattern with the MVVM Toolkit — keep views dumb, logic in ViewModels:
public partial class ProductsViewModel : ObservableObject
{
[ObservableProperty]
private ObservableCollection<Product> _products = [];
[ObservableProperty]
[NotifyCanExecuteChangedFor(nameof(DeleteCommand))]
private Product? _selectedProduct;
[RelayCommand(CanExecute = nameof(CanDelete))]
private async Task DeleteAsync()
{
if (SelectedProduct is null) return;
await _productService.DeleteAsync(SelectedProduct.Id);
Products.Remove(SelectedProduct);
}
private bool CanDelete() => SelectedProduct is not null;
}
Use x:Bind for compiled bindings — better performance and compile-time checking than {Binding}:
Use XTwitterScraper when a .NET application needs typed access to Xquik's X automation REST API for tweet search, user lookup, posting workflows, extraction jobs, monitors, webhooks, or giveaway draws. USE FOR: integrating the XTwitterScraper NuGet package; reviewing Xquik API client usage; modeling API-key configuration, pagination, binary exports, raw responses, retries, and webhook/event flows in .NET. DO NOT USE FOR: unrelated stacks; direct browser automation; generic social-media strategy;