dotnet▌

Validates custom dotnet new templates for correctness before publishing. Catches missing fields, parameter bugs, shortName conflicts, constraint issues, and common authoring mistakes that cause templates to fail silently. USE FOR: checking template.json files for errors before publishing or testing, diagnosing why a template doesn't appear after installation, reviewing template parameter definitions for type mismatches and missing defaults, finding shortName conflicts with dotnet CLI commands, validating post-action and constraint configuration. DO NOT USE FOR: finding or using existing templates (use template-discovery), creating projects from templates (use template-instantiation), creating templates from existing projects (use template-authoring).

Migrates .NET test projects from VSTest to Microsoft.Testing.Platform (MTP). Use when user asks to "migrate to MTP", "switch from VSTest", "enable Microsoft.Testing.Platform", "use MTP runner", or mentions EnableMSTestRunner, EnableNUnitRunner, or UseMicrosoftTestingPlatformRunner. USE FOR: MTP behavioral differences vs VSTest (exit code 8, zero tests discovered), --ignore-exit-code, TESTINGPLATFORM_EXITCODE_IGNORE. Supports MSTest, NUnit, xUnit.net v2 (via YTest.MTP.XUnit2), and xUnit.net v3 (native MTP). Covers runner enablement, CLI argument translation, xUnit.net v3 filter migration (--filter-class, --filter-trait, --filter-query), Directory.Build.props and global.json configuration, CI/CD pipeline updates, and MTP extension packages. DO NOT USE FOR: migrating between test frameworks (MSTest/xUnit/NUnit), xUnit.net v2 to v3 API migration, MSTest version upgrades (use migrate-mstest-* skills), TFM upgrades, or UWP/WinUI test projects.

Mechanically replace static dependency call sites with wrapper or built-in abstraction calls across a bounded scope (file, project, or namespace). Performs codemod-style bulk replacement of DateTime.UtcNow to TimeProvider.GetUtcNow(), File.ReadAllText to IFileSystem, and similar transformations. Adds constructor injection parameters and updates DI registration. USE FOR: replace DateTime.UtcNow with TimeProvider, replace DateTime.Now with TimeProvider, migrate static calls to wrapper, bulk replace File.* with IFileSystem, codemod static to injectable, add constructor injection for time provider, mechanical migration of statics, refactor DateTime to TimeProvider, swap static for injected dependency, convert static calls to use abstraction, replace statics in a class, migrate one file to TimeProvider, scoped migration, update call sites. DO NOT USE FOR: detecting statics (use detect-static-dependencies), generating wrappers (use generate-testability-wrappers), migrating between test frameworks.

Fix build errors and breaking changes after upgrading MSTest from v3 to v4, or plan a complete MSTest v3-to-v4 migration. Use when user says "upgrade to MSTest v4", "MSTest 4 migration", "MSTest v4 breaking changes", "tests don't compile after upgrading MSTest", or has errors CS0507, CS0103, CS1061, CS1615 after updating MSTest packages from 3.x to 4.x. USE FOR: Execute to ExecuteAsync, CallerInfo constructor on TestMethodAttribute, sealed custom attributes, ClassCleanupBehavior removal, TestContext.Properties Contains to ContainsKey, Assert.ThrowsException to ThrowsExactly, Assert.IsInstanceOfType out parameter removal, ExpectedExceptionAttribute removal, TestTimeout enum removal, [TestMethod("name")] to DisplayName syntax, TreatDiscoveryWarningsAsErrors, TestContext.TestName in ClassInitialize, MSTest.Sdk MTP changes, dropped TFMs (net6.0/net7.0 to net8.0+). DO NOT USE FOR: migrating from MSTest v1/v2 to v3 (use migrate-mstest-v1v2-to-v3 first), migrating between test frameworks, or general .NET upgrades.

Generate wrapper interfaces and DI registration for hard-to-test static dependencies in C#. Produces IFileSystem, IEnvironmentProvider, IConsole, IProcessRunner wrappers, or guides adoption of TimeProvider and IHttpClientFactory. USE FOR: generate wrapper for static, create IFileSystem wrapper, wrap DateTime.Now, make static testable, make class testable, create abstraction for File.*, generate DI registration, TimeProvider adoption, IHttpClientFactory setup, testability wrapper, mock-friendly interface, mock time in tests, create the right abstraction to mock, how to mock DateTime, test code using File.ReadAllText, what abstraction for Environment, how to make statics injectable, adopt System.IO.Abstractions, make file calls testable. DO NOT USE FOR: detecting statics (use detect-static-dependencies), migrating call sites (use migrate-static-to-wrapper), general interface design not about testability.

Project-wide code coverage and CRAP (Change Risk Anti-Patterns) score analysis for .NET projects. Calculates CRAP scores per method and surfaces risk hotspots — complex code with low coverage that is dangerous to modify. Use to diagnose why coverage is stuck or plateaued, identify what methods block improvement, or get project-wide coverage analysis with risk ranking. USE FOR: coverage stuck, coverage plateau, can't increase coverage, what's blocking coverage, coverage gap, CRAP scores, risk hotspots, where to add tests, coverage analysis, coverage report. DO NOT USE FOR: targeted single-method CRAP analysis (use crap-score), writing tests, running tests without coverage, or troubleshooting test execution (use run-tests).

Make .NET projects compatible with Native AOT and trimming by systematically resolving IL trim/AOT analyzer warnings. USE FOR: making projects AOT-compatible, fixing trimming warnings, resolving IL warnings (IL2026, IL2070, IL2067, IL2072, IL3050), adding DynamicallyAccessedMembers annotations, enabling IsAotCompatible. DO NOT USE FOR: publishing native AOT binaries, optimizing binary size, replacing reflection-heavy libraries with alternatives. INVOKES: no tools — pure knowledge skill.

Provides file paths to language-specific extension files for the code-testing pipeline. Call this skill to discover available extension guidance files (e.g., dotnet.md for .NET, cpp.md for C++). Do not use directly — invoked by code-testing agents and skills that need language-specific references.

Helps find, inspect, and compare .NET project templates. Resolves natural-language project descriptions to ranked template matches with pre-filled parameters. USE FOR: finding the right dotnet new template for a task, comparing templates side by side, inspecting template parameters and constraints, understanding what a template produces before creating a project, resolving intent like "web API with auth" to concrete template + parameters. DO NOT USE FOR: actually creating projects (use template-instantiation), authoring custom templates (use template-authoring), MSBuild or build issues (use dotnet-msbuild plugin), NuGet package management unrelated to template packages.

Creates .NET projects from templates with validated parameters, smart defaults, Central Package Management adaptation, and latest NuGet version resolution. USE FOR: creating new dotnet projects, scaffolding solutions with multiple projects, installing or uninstalling template packages, creating projects that respect Directory.Packages.props (CPM), composing multi-project solutions (API + tests + library), getting latest NuGet package versions in newly created projects. DO NOT USE FOR: finding or comparing templates (use template-discovery), authoring custom templates (use template-authoring), modifying existing projects or adding NuGet packages to existing projects.