A reference skill for building Avalonia user interfaces, a .NET framework for making apps that run on desktop, mobile, and web platforms. It covers layout, styling, data binding, controls, animation, and deployment.

Use it when creating or changing Avalonia screens, including XAML markup, layouts, styles, bindings, controls, animations, custom controls, input handling, and deployment.

It helps an agent choose the relevant Avalonia guidance before writing or reviewing code. This reduces mistakes across Avalonia’s many UI features and supported platforms.

avalonia — Skill for Claude Code and Codex by linuxdevel

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add linuxdevel/Avalonia-skills --skill avalonia

Clone the repo

git clone --depth 1 https://github.com/linuxdevel/Avalonia-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/linuxdevel/avalonia-skills/avalonia/github.svg)](https://agentmods.dev/skills/linuxdevel/avalonia-skills/avalonia)

Your own site

<a href="https://agentmods.dev/skills/linuxdevel/avalonia-skills/avalonia"><img src="https://agentmods.dev/badge/skills/linuxdevel/avalonia-skills/avalonia/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/linuxdevel/avalonia-skills/avalonia"><img src="https://agentmods.dev/badge/skills/linuxdevel/avalonia-skills/avalonia.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 30 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,082 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00030	$0.01082
Opus 5.5	$0.00012	$0.00433
Sonnet 5.5	$0.00006	$0.00216
Haiku 4.5	$0.00003	$0.00108

Measured 9d ago against content hash 90bfa1fa89bc, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

avalonia scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (avalonia-pro-max/preview-server/scripts/render_variants.py, avalonia-pro-max/preview-server/scripts/scaffold_host.py, avalonia-pro-max/preview-server/scripts/serve_gallery.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/avalonia/SKILL.md · 68 lines

How it starts

The opening of the file, as written. The whole thing — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Avalonia UI

Overview

Avalonia is a cross-platform .NET UI framework using XAML (.axaml), with its own Skia-based rendering engine, supporting Windows, macOS, Linux, iOS, Android, and WASM.

Supported versions: 11.3 (legacy), 12.0, 12.1 (current stable, 12.1.4). Default for new projects: latest 12.1.x on net10.0.

Rule 1 — version first: Before writing or reviewing code, detect the project's Avalonia version (Avalonia PackageReference in *.csproj / Directory.Packages.props). Many APIs differ between 11.x and 12.x (clipboard, drag-drop, Android lifetime, Watermark, window decorations, compiled-binding default). Load avalonia-versions when unsure whether a feature exists in that version, or when migrating/upgrading.

Rule 2: Always load the matching subskill before writing or reviewing Avalonia code. Subskills mark version-specific content as (12.0+), (12.1+) or (11.x); unlabelled content works in all supported versions.

Routing Table

Task	Load subskill
Which version? Feature availability, 11→12 migration, 12.0→12.1 upgrade	`avalonia-versions`
XAML markup, .axaml files, namespaces, code-behind	`avalonia-xaml`
Panels, Grid, StackPanel, alignment, margins	`avalonia-layout`
Styles, control themes, selectors, pseudoclasses, themes	`avalonia-styling`
`{Binding}`, compiled bindings, converters, validation	`avalonia-data-binding`
DataTemplate, ItemTemplate, template selection	`avalonia-data-templates`
MVVM pattern, INotifyPropertyChanged, ICommand, CommunityToolkit	`avalonia-mvvm`
Built-in controls (Button, TextBox, GroupBox, TableView, DataGrid, pages, etc.)	`avalonia-controls`
Custom UserControl, TemplatedControl, drawing controls	`avalonia-custom-controls`
Brushes, transforms, animations, transitions	`avalonia-graphics-animation`
Pointer, keyboard, gestures, drag-and-drop	`avalonia-input-interaction`
StyledProperty, DirectProperty, AttachedProperty	`avalonia-property-system`
Routed events, bubbling, tunneling	`avalonia-events`
Clipboard, file dialogs, notifications, storage	`avalonia-services`
App structure, resource dictionaries, app lifetime	`avalonia-app-development`
Headless testing, UI automation	`avalonia-testing`
Packaging for macOS/Windows/Linux/WASM	`avalonia-deployment`
Migrating from WPF	`avalonia-wpf-migration`
UI thread, `Dispatcher`, async/await, background work, timers	`avalonia-threading`
Android/iOS app concerns: lifetimes, safe areas, soft keyboard, back button, haptics	`avalonia-mobile`
Composition API, direct Skia/OpenGL, `NativeControlHost`, embedding Avalonia in WinForms/WPF/WinUI	`avalonia-interop-rendering`
Slow UI, profiling, DevTools, virtualization, startup time, trimming, NativeAOT	`avalonia-performance`
Designing/polishing UI for visual quality, picking themes, building a design system, motion, accessibility, layout patterns, icons, pre-ship review	`avalonia-pro-max`

Read the full file on GitHub · 68 lines

Files

What ships with it

47 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

9d ago Changed · +9 lines 90bfa1fa89bc
2mo ago First seen · 59 lines · 30 tokens per session scan A e5d7b4b9ee2d

Subscribe to this mod's changes

avalonia is a skill published in the GitHub repository linuxdevel/Avalonia-skills (48 stars, last pushed 10d ago), licensed MIT. It adds 30 tokens to every session and 1,082 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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