AI agent skills for building Avalonia cross-platform .NET apps
Skill Claude CodeCodex
Use before merging a PR or shipping a release of an Avalonia app — exhaustive pre-delivery checklist covering visual quality, interaction, light/dark, layout, accessibility, performance, motion, and platform parity. Run end-to-end; fix everything before sign-off.
Skill Claude CodeCodex
Use when choosing or configuring a theme library for an Avalonia app (FluentTheme, FluentAvalonia, SukiUI, Semi.Avalonia, Material.Avalonia, ShadUI, Ursa.Avalonia, Citrus, Classic). Provides a recommendation matrix by product type, install snippets, and combination rules.
Skill Claude CodeCodex
Use when working with Avalonia's property system: StyledProperty, DirectProperty, AttachedProperty, property inheritance, metadata override, coercion, value priority, or observing property changes via GetObservable or OnPropertyChanged.
Skill Claude CodeCodex
Use when applying styles, control themes, pseudoclasses, style selectors, theme variants, or custom fonts in Avalonia. Covers Style vs ControlTheme distinction, selector syntax, nested styles, light/dark theme variants, style sharing via avares://, StyleKeyOverride, and style precedence rules.
Skill Claude CodeCodex
Use when writing tests for Avalonia apps — headless UI testing, ViewModel unit tests, UI automation, or setting up the Avalonia test infrastructure.
Skill Claude CodeCodex
Use when migrating a WPF application to Avalonia, mapping WPF concepts to Avalonia equivalents, or understanding differences between WPF and Avalonia APIs.
Skill Claude CodeCodex
Use when writing or reviewing Avalonia XAML markup, .axaml files, XML namespaces, code-behind, markup extensions, or building UI without XAML in code.
Skill Claude CodeCodex
Use when going beyond Render()/DrawingContext in Avalonia — Composition API (ElementComposition, CompositionCustomVisualHandler, implicit animations), ICustomDrawOperation with direct SkiaSharp access, OpenGlControlBase, WriteableBitmap/ILockedFramebuffer pixel work, NativeControlHost embedding native HWND/NSView…
Skill Claude CodeCodex
Use when building or fixing the Android or iOS (and Mac Catalyst) app side of an Avalonia app — project heads and startup per version (AvaloniaAndroidApplication, AvaloniaMainActivity, AvaloniaAppDelegate, IActivityApplicationLifetime vs ISingleViewApplicationLifetime), safe areas/edge-to-edge (IInsetsManager), soft…
Skill Claude CodeCodex
Use when diagnosing or improving Avalonia performance — slow scrolling or large lists (virtualization, TableView), FPS/layout/render profiling with DevTools and RendererDiagnostics overlays, compiled vs reflection bindings, image decode size, visual-tree depth, startup time and size (ReadyToRun, trimming, NativeAOT)…
Skill Claude CodeCodex
Use when code touches Avalonia threading — updating UI from background threads, Dispatcher.UIThread Post/InvokeAsync/Invoke, CheckAccess/VerifyAccess ("Call from invalid thread"), DispatcherPriority, async/await in ViewModels, ConfigureAwait, DispatcherTimer, progress reporting, cancellation, ObservableCollection…
Skill Claude CodeCodex
Use FIRST when the Avalonia version matters — detecting which Avalonia version a project uses, checking whether a feature/API exists in 11.3, 12.0 or 12.1, migrating 11.x → 12.x, or upgrading 12.0 → 12.1. Contains the version/feature matrix, renamed/removed API tables, and the version-label conventions used by all…
At most 3 mods per repository are shown here, and a mod shipped inside a plugin is left to that plugin's page — the rest are on their repository pages: