Official agent skill

MAUI XAML Unit Test Writer

Writes a paired .xaml and .xaml.cs unit test for a .NET MAUI issue that is about XAML behavior itself, such as parsing, XamlC output or generated code.

OfficialMITAuto-check passedTesting & QA

Install MAUI XAML Unit Test Writer

skills CLI

$ npx skills add dotnet/maui --skill write-xaml-tests -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install dotnet/maui write-xaml-tests --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/dotnet/maui.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.github/skills/write-xaml-tests .claude/skills/write-xaml-tests && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "write-xaml-tests" agent skill from https://github.com/dotnet/maui/tree/main/.github/skills/write-xaml-tests into .claude/skills/write-xaml-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "write-xaml-tests", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/dotnet/maui/tree/main/.github/skills/write-xaml-tests

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add dotnet/maui --skill write-xaml-tests -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install dotnet/maui write-xaml-tests --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/dotnet/maui.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.github/skills/write-xaml-tests .agents/skills/write-xaml-tests && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "write-xaml-tests" agent skill from https://github.com/dotnet/maui/tree/main/.github/skills/write-xaml-tests into .agents/skills/write-xaml-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "write-xaml-tests", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add dotnet/maui --skill write-xaml-tests -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install dotnet/maui write-xaml-tests --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/dotnet/maui.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.github/skills/write-xaml-tests .cursor/skills/write-xaml-tests && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "write-xaml-tests" agent skill from https://github.com/dotnet/maui/tree/main/.github/skills/write-xaml-tests into .cursor/skills/write-xaml-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "write-xaml-tests", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/dotnet/maui.git --path .github/skills/write-xaml-tests

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add dotnet/maui --skill write-xaml-tests -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install dotnet/maui write-xaml-tests --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/dotnet/maui.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.github/skills/write-xaml-tests .gemini/skills/write-xaml-tests && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "write-xaml-tests" agent skill from https://github.com/dotnet/maui/tree/main/.github/skills/write-xaml-tests into .gemini/skills/write-xaml-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "write-xaml-tests", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install dotnet/maui write-xaml-tests

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add dotnet/maui --skill write-xaml-tests -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/dotnet/maui.git skills-src && mkdir -p .github/skills && cp -r skills-src/.github/skills/write-xaml-tests .github/skills/write-xaml-tests && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "write-xaml-tests" agent skill from https://github.com/dotnet/maui/tree/main/.github/skills/write-xaml-tests into .github/skills/write-xaml-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "write-xaml-tests", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add dotnet/maui --skill write-xaml-tests -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install dotnet/maui write-xaml-tests --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/dotnet/maui.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.github/skills/write-xaml-tests .opencode/skills/write-xaml-tests && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "write-xaml-tests" agent skill from https://github.com/dotnet/maui/tree/main/.github/skills/write-xaml-tests into .opencode/skills/write-xaml-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "write-xaml-tests", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: write-xaml-tests
GitHub stars: 23k
Token cost: ~742 tokens
SKILL.md length: 200 words
Files: 1
Skills in repo: 27
Repo updated: Oct 7, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Writes a paired .xaml and .xaml.cs unit test for a .NET MAUI issue that is about XAML behavior itself, such as parsing, XamlC output or generated code.

Works in 4 steps: Read the XAML Unit Test Guidelines → Create Test Files → Verify Tests Compile and Run → …
Testing XAML parsing or inflation behavior for a reported bug
SKILL.md covers When to Use, When NOT to Use, Required Input and Workflow, plus 2 more sections
Calls dotnet

What it does

The skill is for bugs that are specific to XAML, such as bindings, markup extensions or x:Name, and not for UI interactions or rendering, which belong to the write-ui-tests skill. The input is an issue number, a description of the broken XAML behavior and the expected versus actual result. The agent first reads the repository's XAML unit test guidelines, which set file naming, the Issues folder under src/Controls/tests/Xaml.UnitTests, the XamlInflator values pattern, MockCompiler for XamlC tests, MockSourceGenerator for generator tests and special extensions for invalid codegen.

It then creates a paired .xaml and .xaml.cs test file for the issue, builds the test project with dotnet and runs the tests. A bug reproduction test should fail before the fix and pass after it, while a regression test should simply pass. At the end the agent reports the files it created in a fixed summary format. Building and running the xUnit tests needs the .NET SDK.

When your agent uses it

Testing XAML parsing or inflation behavior for a reported bug
Checking XamlC compilation output for a XAML construct
Verifying source generator output for a XAML-specific issue

Example prompts

“Add a XAML unit test for issue 12345, where an x:Name reference fails to resolve.”
“Write a regression test for this markup extension bug in Controls.Xaml.UnitTests.”
“Create a source generator test that reproduces the binding problem described in the issue.”

Requirements

.NET SDK for building and running xUnit tests
Compatibility (from SKILL.md): Requires .NET SDK for building and running xUnit tests.

Workflow steps

4 steps, taken from the step headings in SKILL.md.

Read the XAML Unit Test Guidelines
Create Test Files
Verify Tests Compile and Run
Verify Test Behavior

What it can do on your machine

Read from SKILL.md and the folder at commit 7d38fd0. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
- dotnet
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Compatibility
Requires .NET SDK for building and running xUnit tests.
From compatibility in the SKILL.md frontmatter.

Context cost

MAUI XAML Unit Test Writer loads about 742 tokens when it runs. Until then it costs about 56 tokens; SKILL.md has 200 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~56
When it runs · the whole SKILL.md, loaded when a task matches: ~742

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from dotnet/maui at commit 7d38fd0, republished under its MIT licence (© dotnet). 200 words, ~742 tokens.

Download SKILL.mdSave it as .claude/skills/write-xaml-tests/SKILL.md (or your agent's skills folder).

name: write-xaml-tests
description: Creates XAML unit tests for GitHub issues in the Controls.Xaml.UnitTests project. Tests XAML parsing, compilation (XamlC), and source generation. Use when testing XAML-specific behavior, not UI interactions.
compatibility: Requires .NET SDK for building and running xUnit tests.
metadata.author: Stephane Delcroix
metadata.version: 1.0

Write XAML Tests Skill

Creates XAML unit tests that verify XAML parsing, XamlC compilation, and source generation behavior.

When to Use

✅ Testing XAML parsing/inflation behavior
✅ Testing XamlC (IL generation) correctness
✅ Testing Source Generator output
✅ XAML-specific bugs (bindings, markup extensions, x:Name, etc.)

When NOT to Use

❌ Testing UI interactions or visual behavior → Use write-ui-tests skill
❌ Testing runtime behavior after page loads → Use write-ui-tests skill
❌ Testing platform-specific rendering → Use write-ui-tests skill

Required Input

Before invoking, ensure you have:

Issue number (e.g., 12345)
Issue description - what XAML behavior is broken
Expected vs actual behavior

Workflow

Step 1: Read the XAML Unit Test Guidelines

bash

cat .github/instructions/xaml-unittests.instructions.md

This contains the authoritative conventions for:

File naming (MauiXXXXX.xaml and MauiXXXXX.xaml.cs)
File location (src/Controls/tests/Xaml.UnitTests/Issues/)
Test patterns with [Values] XamlInflator
XamlC testing with MockCompiler
Source Generator testing with MockSourceGenerator
Special file extensions for invalid codegen (.rt.xaml, .rtsg.xaml, .rtxc.xaml)

Step 2: Create Test Files

Following the conventions from Step 1, create:

src/Controls/tests/Xaml.UnitTests/Issues/MauiXXXXX.xaml
src/Controls/tests/Xaml.UnitTests/Issues/MauiXXXXX.xaml.cs

Step 3: Verify Tests Compile and Run

bash

# Build the test project
dotnet build src/Controls/tests/Xaml.UnitTests/Controls.Xaml.UnitTests.csproj -c Debug --no-restore -v q

# Run specific test
dotnet test src/Controls/tests/Xaml.UnitTests/Controls.Xaml.UnitTests.csproj --filter "FullyQualifiedName~MauiXXXXX" --no-build

Step 4: Verify Test Behavior

For bug reproduction tests: Tests should FAIL before fix, PASS after fix
For regression tests: Tests should PASS to confirm behavior works

Output

After completion, report:

markdown

✅ XAML unit test created for Issue #XXXXX

**Files:**
- `src/Controls/tests/Xaml.UnitTests/Issues/MauiXXXXX.xaml`
- `src/Controls/tests/Xaml.UnitTests/Issues/MauiXXXXX.xaml.cs`

**Test method:** `DescriptiveTestName`
**Inflators tested:** Runtime, XamlC, SourceGen
**Verification:** Tests [PASS/FAIL] as expected

References

Full conventions: .github/instructions/xaml-unittests.instructions.md
Test project: src/Controls/tests/Xaml.UnitTests/
Existing issue tests: src/Controls/tests/Xaml.UnitTests/Issues/

Files

Just SKILL.md in .github/skills/write-xaml-tests of dotnet/maui.

Open the folder on GitHubat commit 7d38fd0

Compare with similar skills

MAUI XAML Unit Test Writer next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

MAUI XAML Unit Test Writer compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
MAUI XAML Unit Test Writer this skilldotnet/maui	23k	—	~742	Automated safety check: Pass	MIT	yesterday
ScottPlot Test RunnerScottPlot/ScottPlot	6.8k	—	~308	Automated safety check: Pass	MIT	1 mo ago
Run Testsrunceel/ReactiveProperty	944	—	~3.6k	Automated safety check: Pass	MIT	1 mo ago
Code Testing Agentmicrosoft/testfx	1k	—	~2.7k	Automated safety check: Pass	MIT	today
Run Testsmicrosoft/testfx	1k	—	~4.2k	Automated safety check: Pass	MIT	today
Test Taggingmicrosoft/testfx	1k	—	~4.3k	Automated safety check: Pass	MIT	today

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Questions about MAUI XAML Unit Test Writer

What does MAUI XAML Unit Test Writer do?

Writes a paired .xaml and .xaml.cs unit test for a .NET MAUI issue that is about XAML behavior itself, such as parsing, XamlC output or generated code. The skill is for bugs that are specific to XAML, such as bindings, markup extensions or x:Name, and not for UI interactions or rendering, which belong to the write-ui-tests skill. The input is an issue number, a description of the broken XAML behavior and the expected versus actual result.

When should I use MAUI XAML Unit Test Writer?

MAUI XAML Unit Test Writer fits situations like: testing XAML parsing or inflation behavior for a reported bug; checking XamlC compilation output for a XAML construct; verifying source generator output for a XAML-specific issue.

How do I install MAUI XAML Unit Test Writer in Claude Code?

Run `npx skills add dotnet/maui --skill write-xaml-tests -a claude-code`. Or copy the skill folder (.github/skills/write-xaml-tests in dotnet/maui) into .claude/skills/write-xaml-tests in your project. Claude Code loads it when a task matches its description.

How do I install MAUI XAML Unit Test Writer in Codex?

Run `npx skills add dotnet/maui --skill write-xaml-tests -a codex`. Or copy the skill folder (.github/skills/write-xaml-tests in dotnet/maui) into .agents/skills/write-xaml-tests in your project. Codex loads it when a task matches its description.

Can I use MAUI XAML Unit Test Writer in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add dotnet/maui --skill write-xaml-tests -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/write-xaml-tests, .gemini/skills/write-xaml-tests, .github/skills/write-xaml-tests and .opencode/skills/write-xaml-tests in your project.

What does MAUI XAML Unit Test Writer need to run?

Going by SKILL.md and its folder, MAUI XAML Unit Test Writer needs the command-line tools its instructions call (dotnet). Our summary lists: .NET SDK for building and running xUnit tests. Compatibility (from SKILL.md): Requires .NET SDK for building and running xUnit tests..

Does MAUI XAML Unit Test Writer access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is MAUI XAML Unit Test Writer safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does MAUI XAML Unit Test Writer use?

MAUI XAML Unit Test Writer is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does MAUI XAML Unit Test Writer use?

About 742 tokens (SKILL.md is roughly 3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to MAUI XAML Unit Test Writer?

Skills that share tags, products or a category with MAUI XAML Unit Test Writer: ScottPlot Test Runner (ScottPlot/ScottPlot, 6.8k stars), Run Tests (runceel/ReactiveProperty, 944 stars), Code Testing Agent (microsoft/testfx, 1k stars) and Run Tests (microsoft/testfx, 1k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains MAUI XAML Unit Test Writer?

dotnet (a GitHub organization, an official publisher) maintains it in dotnet/maui, which has 23,322 GitHub stars. The repository holds 27 skills in this directory. The repository was last updated on October 7, 2026.

Source: dotnet/maui on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install MAUI XAML Unit Test Writer

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Compatibility

Context cost

Safety

SKILL.md

Write XAML Tests Skill

When to Use

When NOT to Use

Required Input

Workflow

Step 1: Read the XAML Unit Test Guidelines

Step 2: Create Test Files

Step 3: Verify Tests Compile and Run

Step 4: Verify Test Behavior

Output

References

Files

Compare with similar skills

Similar skills

More from dotnet/maui

Related

Questions about MAUI XAML Unit Test Writer