dotnet

Pseudo-mutation analysis ONLY: find caller-visible production-code changes that existing assertions would not catch, then optionally close verified gaps. Activate only when the request asks whether a bug/change/mutation could survive, names behavioral blind…

Scaffolds eval.yaml evaluation specs for agent skills in the dotnet/skills repository. Use when creating skill tests, writing evaluation stimuli, defining graders and rubrics, sizing an eval for statistical power, or setting up test fixture files. Handles the…

Diagnoses and fixes skills in the dotnet/skills repository that lose to their own baseline, fail to activate, time out, or return "no credible improvement". Use when an evaluation verdict is a regression or underpowered, when a skill regressed after a change,…

Fix build errors and breaking changes after upgrading MSTest v3 to v4, or plan a complete 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 3.x to…

Convert .NET test projects from xUnit.net v2 or v3 to MSTest v4. Use for replacing xunit packages, [Fact]/[Theory], xUnit assertions, fixtures, ITestOutputHelper, traits, skips, and xUnit parallelization with MSTest equivalents while preserving the current…

Migrates .NET test projects from xUnit.net v2 to xUnit.net v3. USE FOR: upgrading xunit to xunit.v3. DO NOT USE FOR: migrating between test frameworks (MSTest/NUnit to xUnit.net), migrating from VSTest to Microsoft.Testing.Platform (use…

Report assertion quality in existing tests. ALWAYS USE for weak, shallow, trivial, always-true, self-referential, assertion-free, presence/truthiness-only, or insufficiently diverse assertions. Polyglot. DO NOT USE for direct fixes: writing-mstest-tests owns…

Interprets .NET Cobertura line, branch, and condition evidence and, when explicitly requested, computes project-wide CRAP/refactoring-risk hotspots. MUST USE for "why is branch coverage lower than line coverage?", condition-coverage="50% (1/2)", a supplied…

Make .NET MAUI apps accessible with semantic properties, screen reader labels/hints, heading levels, focus, announcements, AutomationProperties, touch targets, and platform checks. USE FOR: accessibility audits, WCAG UI fixes, TalkBack/VoiceOver/Narrator…

Use `Microsoft.Maui.AI.Attributes` to source-generate `Microsoft.Extensions.AI` tools for MAUI apps. USE FOR: `ExportAIFunction`, `AIToolSource`, `AIToolContext`, `Default.Tools`, DI-bound parameters, chat-session scopes, AOT-safe tools, and…

Design .NET MAUI architecture around DI, MVVM, compiled bindings, Shell navigation, route registration, query parameters, and testable services. USE FOR: MauiProgram service registration, page/ViewModel wiring, Shell GoToAsync, Routing.RegisterRoute,…

Configure .NET MAUI app icons, splash screens, images, fonts, bundled files, app/window lifecycle, background/resume state, and platform asset/lifecycle settings. USE FOR: MauiIcon, MauiSplashScreen, MauiImage, MauiFont, MauiAsset, Resources/Images,…

Connect MAUI apps to Aspire-hosted APIs. USE FOR: `AddServiceDiscovery`, typed `HttpClient`, `https+http://apiservice`, missing AppHost config on devices, Android emulator `10.0.2.2`, iOS simulator `localhost`, physical-device LAN/dev-tunnel fallbacks, dev…

Implement .NET MAUI authentication and secure storage flows with WebAuthenticator, MSAL.NET, platform callback URIs, token caches, brokers, SecureStorage, logout cleanup, and Blazor Hybrid auth handoff. USE FOR: login/logout, OAuth/OIDC redirects, Entra ID,…

Build and debug .NET MAUI Blazor Hybrid features with BlazorWebView, HybridWebView, Razor components, static assets, JS/.NET interop, trimming/NativeAOT concerns, and DevFlow CDP route inspection. USE FOR: MAUI apps hosting Razor UI, embedded HTML/JS,…

Apply advanced MAUI control guidance. USE FOR: `CollectionView` incremental loading, `RemainingItemsThreshold`, `EmptyView`, `AutomationId`, avoiding `ScrollView` wrappers, `SafeAreaEdges` on .NET 10, `GraphicsView`/`IDrawable`/`Invalidate` hot-path…

Labels issues and pull requests in the dotnet/maui repository with `area-*` and `platform/*` labels ONLY, based on technical content and platform-file conventions. Used by the gh-aw agentic-labeler workflow and available for batch evaluation and interactive…

Analyzes your local Copilot CLI sessions for dotnet/maui to drive iterative improvements to the PR-review agent (and other agents, skills, and instruction files). Runs a select → extract → score → judge → cluster → propose → emit-eval loop: a deterministic…

Deep code review of PR or materialized candidate-patch changes for correctness, safety, and MAUI conventions. Uses independence-first assessment (code before narrative) and delegates to the maui-expert-reviewer agent for per-dimension sub-agent evaluation.…

Evaluates tests added in a PR for coverage, quality, edge cases, and test type appropriateness. Checks if tests cover the fix, finds gaps, and recommends lighter test types when possible. Prefer unit tests over device tests over UI tests. Triggers on:…

End-to-end PR reviewer for dotnet/maui. Orchestrates 3 phases — Pre-Flight, Try-Fix, Report. Gate runs separately before this skill. Use when asked to 'review PR #XXXXX', 'work on PR #XXXXX', or 'fix issue #XXXXX'.

Attempts ONE alternative fix for a bug, tests it empirically, and reports results. ALWAYS explores a DIFFERENT approach from existing PR fixes. Use when CI or an agent needs to try independent fix alternatives. Invoke with problem description, test command,…

Verifies tests catch the bug. Auto-detects test type (UI tests, device tests, unit tests) and dispatches to the appropriate runner. Supports two modes - verify failure only (test creation) or full verification (test + fix validation).

Assesses ship-readiness for .NET MAUI release branches — Servicing Releases (SR) and Previews — and produces public-safe, copy-ready release handoffs or Loop-page drafts from the resulting evidence. Use for readiness verdicts, release blockers, Preview/SR…

Resolve a CoreCLR runtime test from a generated .cmd or .sh wrapper path for the standalone-test-repro workflow. Use when the requested test is identified by a CI or Helix wrapper path, with or without a named test scenario. Continue with the parent…

Resolve a CoreCLR runtime test from a fully qualified method name for the standalone-test-repro workflow. Use for xUnit display names and methods in merged or multi-test assemblies, with or without a named test scenario. Continue with the parent…

Generate a standalone console application under artifacts/tmp from a managed test under src/tests so it can be run directly with corerun. USE FOR: "create a standalone repro for this runtime test", converting a CoreCLR test wrapper path such as…

Generate a CoreRun-compatible .env file for a named CoreCLR test scenario defined by src/tests/Common/testenvironment.proj. Optionally merge the effective common and target-specific environment items from a specific src/tests project. USE FOR: "create an env…

Create or update a Known Build Error issue in dotnet/runtime from a concrete CI failure. Use when a failure is actionable, a Build Analysis result is not yet known, or a workflow needs a repo-specific KBE issue for an outer-loop or PR-targeted failure.

Update OS version references in Helix queue definitions to add new versions, replace EOL versions, or audit coverage against the supported-os matrix. USE FOR: adding new OS versions to Helix queues, replacing EOL OS versions, upgrading "oldest" or "latest"…

Review code changes in dotnet/runtime for correctness, performance, and consistency with project conventions. Use when reviewing PRs or code changes.

Create prototype-backed API proposals for dotnet/runtime. Use when asked to draft an API proposal, write an api-suggestion issue, refine a vague API idea into a complete proposal, or improve a proposal marked api-needs-work. Covers the full pipeline from…

Orchestrate an MSBuild release: create the tracking issue, branch, configure DARC channels and subscriptions, bump version in main, final-brand the release branch, insert into VS, and publish post-GA. Covers the full monthly release lifecycle aligned with VS…

Guide for migrating MSBuild tasks to multithreaded mode support, including compatibility red-team review. Use this when converting tasks to thread-safe versions, implementing IMultiThreadableTask, adding TaskEnvironment support, or auditing migrations for…

Guide for running MSBuild unit tests efficiently. Use when running, scoping, filtering, or speeding up unit tests in this repository, or when finalizing a change with a heavier validation pass. Covers xUnit v3 + Microsoft.Testing.Platform (MTP) specifics and…

Review and merge open bot PRs: dependency updates from dotnet-maestro, codeflow from dotnet/dotnet, and OneLoc localization PRs. Produces a clickable dashboard with CI status, review state, and suspicious file flags. Use when you want to triage all open bot…

Guides struct-based COM interop in MSBuild using CsWin32 patterns. Consult when working with ComScope<T>, ComClassFactory, IComIID, IID.Get<T>(), delegate* unmanaged vtables, CoCreateInstance, or manually defining COM interfaces not in Win32 metadata (e.g.…

Guides CsWin32 P/Invoke interop in MSBuild. Consult when working with the PInvoke class, Windows.Win32 namespaces, FEATURE_WINDOWSINTEROP, HANDLE/HMODULE/HRESULT types, BufferScope<T>, replacing [DllImport] with CsWin32, or conditioning Windows-only code for…

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…

GitHub issue and project-board management for the dotnet/msbuild repo. Use when asked to file/triage/update issues, post comments, amend issue bodies, move sprints, bulk-update project board fields, or audit items by sprint/status/assignee.

Implementation details for EF Core test infrastructure. Use when changing test fixtures, SQL baseline assertions, test helpers, the test class hierarchy, or when adding new tests.

Implementation details for the EF Core Azure Cosmos DB provider. Use when changing Cosmos-specific code.

Run ApiChief in the EF Core repo to emit baselines, summaries, deltas, review files, or breaking-change checks. Use when refreshing `*.baseline.json`, preparing API review artifacts, or validating API changes.

Create custom GitHub Copilot agents. Use when asked to create, scaffold, or configure a custom agent, declarative agent, or @-invokable chat participant for GitHub Copilot.

Create new Agent Skills for GitHub Copilot. Use when asked to create, scaffold, or add a skill. Generates SKILL.md with frontmatter, directory structure, and optional resources.

Implementation details for EF Core migrations. Use when changing MigrationsSqlGenerator, model diffing, migration operations, HistoryRepository, the Migrator or related classes.

Implementation details for EF Core LINQ query translation, SQL generation, and bulk operations (ExecuteUpdate/ExecuteDelete). Use when changing expression visitors, SqlExpressions, QuerySqlGenerator, ShaperProcessingExpressionVisitor, UpdateExpression,…

Create EF Core PRs targeting servicing release branches (release/*). Use when working on a PR that targets a release branch, backporting a fix from main, or when the user mentions servicing, patch, or release branch.

Generate and maintain .NET release notes from `features.json`. Uses `generate-changes` for authoritative shipped-change data, `generate-features` for scoring/triage, `update-existing-branch` for incremental reruns on populated branches, `editorial-scoring`…

Route gh-aw workflow design/create/debug/upgrade requests to the right prompts.

Generate before/after .NET public API diff reports for a release milestone with `RunApiDiff.ps1`. Pure report generation only; to verify the diff against the shipped build (dotnet-inspect, revert detection) use the api-diff-validation skill.

Validate that a generated API diff matches the APIs actually shipped in a .NET build, and that every new API traces to a real change. Uses dotnet-inspect to query the build's ref packs and cross-references new APIs against candidate PRs to catch missed…

Generate `changes.json` for a .NET release milestone by selecting the correct VMR base/head refs and running `release-notes generate changes`. Handles preview-only multi-branch targeting (`main` vs release branches vs tags) and emits the authoritative…

Refresh an existing .NET release-notes milestone branch set incrementally. Checks whether the VMR ref moved, regenerates `changes.json` only when needed, merges the delta into `features.json`, integrates new material into existing markdown clusters across the…

Create and update per-distro package files in release-notes/{version}/distros/ that document .NET runtime dependencies and package availability for each Linux distribution. USE FOR: setting up distros/ for a new .NET version, updating dependency package names…

Create the GitHub release discussion in dotnet/core and the locked mirror announcement issue in dotnet/announcements for a .NET preview, RC, or GA release. USE FOR: publishing release discussions after release notes exist, mirroring a newly created discussion…

Validate a Blazor feature or behavior interactively in a browser using the canonical Components samples in this repo, before writing E2E tests. USE FOR exercising a Blazor change in src/Components (a render-mode behavior, an interactive component, enhanced…

Orchestrate an MSBuild release: create the tracking issue, branch, configure DARC channels and subscriptions, bump version in main, final-brand the release branch, insert into VS, and publish post-GA. Covers the full monthly release lifecycle aligned with VS…

Guide for migrating MSBuild tasks to multithreaded mode support, including compatibility red-team review. Use this when converting tasks to thread-safe versions, implementing IMultiThreadableTask, adding TaskEnvironment support, or auditing migrations for…

Investigate source-build failures in dotnet/dotnet VMR CI builds. USE FOR any mention of "prebuilt", "source-build/source-only failure", "source-build-assets (SBRP)", "poison", source-build repo build ordering problems, binary detection/removal, or any build…

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Drive the .NET SDK breaking-change documentation-and-notification process for a NuGet change that has already been implemented. Invoke this once a NuGet/Home issue (or its implementing NuGet.Client PR) is labeled `Breaking-Change`. It makes sure the correct…

Cherry-pick (backport/forward-port) one or more commits from one branch onto another, creating a fresh branch and opening a pull request that follows the repository's conventions. Use this whenever the user wants to move, port, backport, or cherry-pick a…

Create or update a pull request using the NuGet.Client PR template. Use when asked to: create PR, open PR, push and create PR, submit PR, open pull request, send changes for review, update PR description, fix PR body, edit PR description, update the PR.

Always invoke after editing `.fs` files under `src/Compiler/`. Fast parse/typecheck without `dotnet build`, plus symbol references and inferred type hints. Use whenever the user asks about F# errors, compile errors, type inference, finding usages, or renaming…

Use when drafting, proposing, creating, or editing prose for a dotnet/fsharp GitHub PR or issue — body, title, comment, review summary, edits — including bare asks like "open a PR", "ship this", "write up what I did", "summarise the change", "reply on the…

Use when a code/test/comment diff is called bloated, slop, LLM slop, bullshit, WTF, crap, rubbish, embarrassing, overengineered, adhoc, or "not paid by LOC"; or when symptoms include bloated comments, superfluous planning .md / .tools / one-time setup /…

Write release notes for completed changes. Use when PR modifies tracked paths and needs release notes entry.

Debug and fix --realsig+ (RealInternalSignature) codegen bugs in IlxGen — MethodAccessException / FieldAccessException / TypeAccessException at runtime, IL `private` vs `assembly` visibility, closure and TLR-lift placement (cloc / NestedTypeRefForCompLoc /…

Fix ILVerify baseline failures when IL shape changes (codegen, new types, method signatures). Use when CI fails on ILVerify job.

Triage a build / compile / restore / WarnAsError failure from its MSBuild binary log. Fetches the binlog (a local build's, or a failed dotnet/fsharp Azure DevOps PR build's published artifact) and analyzes it live via the `binlog-mcp` MCP server — structured…

Investigate compiler failures, test errors, or unexpected behavior through systematic minimal reproduction, 3-hypothesis testing, and verification. Always re-run builds and tests after changes.

Review code changes in dotnet/sdk for problems — either a GitHub pull request or local changes in your branch before a PR exists. Use when asked to review a PR, review local or uncommitted changes, do a code review, check a PR or branch for issues, or review…

Keep dotnet/sdk contributor guidance and agent memory synchronized after code changes. Run at the end of tasks that modify code, move files, change public contracts, alter tests or workflows, establish conventions, or reveal durable repository gotchas.

Add, enable, or review a dotnet CLI command or feature in the Native AOT CLI (src/Cli/dotnet-aot) and prove its compatibility. USE FOR: migrating a command or option to AOT, reviewing an AOT migration PR, defining conservative eligibility and managed…

Add, port, or change a .NET code analysis rule (CA####) under src/Microsoft.CodeAnalysis.NetAnalyzers. USE FOR: implementing a new CA analyzer and its code fixer, porting a rule or PR from the retired dotnet/roslyn-analyzers repo, allocating a diagnostic ID…

Run dotnet.Tests incrementally without a full build.cmd rebuild. Use after modifying source code in SDK projects to quickly build only changed projects, deploy their outputs into the redist SDK layout, and run tests against them.

Migrate .NET test projects from xUnit.net (v2 or v3) to MSTest v4. USE FOR: convert/migrate xUnit tests to MSTest, replace xunit/xunit.v3 packages, port [Fact]/[Theory]/[InlineData]/[MemberData]/[ClassData] to [TestMethod]/[DataRow]/[DynamicData], port…

Select and run .NET SDK tests through the repository's diagnostic-preserving test entry point. REQUIRED whenever an agent will select, run, or rerun local dotnet/sdk tests, including a project, class, method, targeted test, focused test, smallest relevant…

Add or change a dotnet CLI command, subcommand, or option across the relevant CLI projects. USE FOR: adding or changing a dotnet CLI command/subcommand, adding a new Option<T> or Argument<T>, registering a subcommand in the command tree, changing an option's…

Review code changes in dotnet/roslyn for correctness, performance, and consistency with project conventions. Use when reviewing PRs or code changes.

Update the agent knowledge base after making code changes in the Roslyn repo. Run at the end of every task that modifies code, adds files, changes public APIs or diagnostics, or establishes new patterns. Keeps .github/memory/ fresh and reliable.

Perform a branch snap (release branch cut) for dotnet repos like dotnet/roslyn. Use when: snapping a branch, cutting a release branch, creating a release branch, merging main into release, updating VS insertion config, updating darc subscriptions for a snap,…

Set up tracking for a new C# compiler feature: create test plan issue, feature label, update Language Feature Status page, and link related PRs. Use when: setting up a new language feature, creating a test plan, tracking a new csharplang proposal in roslyn,…

Create a merge branch from a chosen base, merge a chosen source/upstream branch into it, resolve common Roslyn conflicts (`.xlf`, `.resx`, compiler codegen), and summarize the resolutions.

Configure a dotnet repository branch to publish build artifacts through a Maestro channel. Use when: publishing branch artifacts to General Testing or another NuGet feed, adding a Darc default channel, enabling official builds for a branch, or setting up…

Install and validate a .NET SDK from an Azure DevOps internal build. Use this when asked to install, validate, or set up a .NET SDK from a dnceng/internal Azure DevOps build link or build ID.

Create or modify Roslyn IDE analyzers, code fixes, and code refactorings. Use when: adding a new IDE diagnostic (IDE0xxx), implementing a CodeFixProvider, implementing a CodeRefactoringProvider, writing analyzer/fixer tests, or working with…

Analyze CI build and test status from Azure DevOps and Helix for dotnet repository PRs. Use when checking CI status, investigating failures, determining if a PR is ready to merge, or given URLs containing dev.azure.com or helix.dot.net. Also use when asked…

Tell the history of a Maestro subscription using the darc CLI's get-subscription-history command. USE FOR: "what happened the last times this subscription ran", "show the trigger history for a subscription", "why did this subscription fail/not update", "did…

Analyze a failed Azure DevOps PR build by reusing the binlog that build already produced — instead of rebuilding locally. Use when an `azure-pipelines` check on a GitHub PR transitions to `failure` and you need a structured root-cause analysis posted back as…

Investigate AzDO pipeline failures beyond Helix — build errors, infra tooling crashes, validation test flakiness, artifact cascade failures. USE FOR: "why did the unified-build fail", "what's breaking the pipeline", "how often does this failure occur", "drill…

Build the Arcade SDK from source, configure a local NuGet feed with the artifacts, and validate the build by running a test repository against the locally-built packages. Use when testing local Arcade changes against a consuming repo, validating Arcade SDK…

Analyze VMR codeflow health using maestro MCP tools and GitHub MCP tools. USE FOR: investigating stale codeflow PRs, checking if fixes have flowed through the VMR pipeline, debugging dependency update issues, checking overall flow status for a repo,…

Trace dependency flow across .NET repos through the VMR pipeline. USE FOR: checking if a PR/commit from repo A has reached repo B, finding what runtime SHA is in an SDK build, tracing dependency versions through the VMR, checking if a commit is included in an…

Analyze historical failure rates for Known Build Error issues by mining the edit history of issue bodies. Use when asked "when did this last fail", "failure history", "failure rate", "is this issue still active", "flaky test history", "known issue activity",…