dotnet

Analyze MSBuild binary logs to diagnose build failures. USE FOR: build errors that are unclear from console output, diagnosing cascading failures across multi-project builds, tracing MSBuild target execution order, and generally any MSBuild build issues.…

Generate MSBuild binary logs (binlogs) for build diagnostics and analysis. USE FOR: adding /bl:{} to any dotnet build, test, pack, publish, or restore command to capture a full build execution trace, prerequisite for binlog-failure-analysis and…

Diagnose MSBuild bottlenecks from binlog timelines and Target/Task Performance Summaries after build-perf-baseline establishes measurements. USE FOR: unknown build slowness, RAR >5s, analyzers >30% of Csc, one target >50% of build time, node utilization <80%,…

Diagnose dotnet-msbuild binlog MCP startup failures. USE FOR: CONNECTION_CLOSED, binlog server won't connect, missing binlog tools, Microsoft.AITools.BinlogMcp not found, dnx launch errors. Checks workspace SDK, feeds, and source mapping without bypassing…

Correctly call native (C/C++) libraries from .NET using P/Invoke and LibraryImport. Covers function signatures, string marshalling, memory lifetime, SafeHandle, and cross-platform patterns. USE FOR: writing new P/Invoke or LibraryImport declarations,…

Establish MSBuild/.NET build performance baselines before optimizing. USE FOR: unranked slow builds; cold, warm, incremental or no-op measurements; before/after comparisons; CI output caching; static graph, artifacts output and dependency graph trimming.…

Remove repeated NuGet restores from multi-step .NET builds safely. USE FOR: build/test/publish steps that each restore, Directory.Build.rsp with -restore, safe restore suppression, NETSDK1004/NETSDK1047 after --no-restore. DO NOT USE FOR: slow first restore,…

Grade curated individual tests for readiness, A-F quality and improvements. ALWAYS USE FOR: grade tests, review only a named test, per-test readiness or quality bands for supplied methods, bodies, file spans or bounded PR diffs, including existing tests.…

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.

USE FOR Xcode 27 compatibility decisions and migration of existing .NET MAUI iOS/Mac Catalyst apps, INCLUDING partially migrated apps that already have scene manifests/delegates but still use AppDelegate or application-level callbacks. Load BEFORE file…

Run DevFlow inspect-and-fix loops for MAUI apps. USE FOR: launch, device selection, agent recovery, broker/port/adb, tree/screenshot, Blazor CDP, and iterative UI debugging. DO NOT USE FOR: first-time setup or non-MAUI automation. INVOKES: DevFlow `maui_*`…

Write and repair C# bindings for Java/Kotlin Android libraries with .NET for Android. USE FOR: direct/full AAR or JAR bindings, AndroidMavenLibrary, Metadata.xml, Additions, missing generated APIs, Kotlin JVM signatures, binding-generator warnings,…

Create Android slim bindings for MAUI/.NET Android. USE FOR: Native Library Interop, thin Kotlin/Java wrapper design, building wrapper AARs with Gradle, Java-friendly callbacks, @JvmStatic, and dependencies of slim wrappers. DO NOT USE FOR: direct/full…

Run DevFlow inspect-and-fix loops for MAUI apps. USE FOR: launch, device selection, agent recovery, broker/port/adb, tree/screenshot, Blazor CDP, and iterative UI debugging. DO NOT USE FOR: first-time setup or non-MAUI automation. INVOKES: DevFlow `maui_*`…

Add MAUI DevFlow to a .NET MAUI project with agent package references, MauiProgram.cs registration, Blazor WebView support, GTK variants, Central Package Management guidance, and verification commands. USE FOR: first-time DevFlow setup, reviewing what files…

Legacy DevFlow debug skill. USE FOR: `maui-ai-debugging`, `maui devflow`, screenshots, visual tree, Blazor CDP, simulator/emulator debugging. DO NOT USE FOR: setup, desktop automation, AppleScript, host `xdotool`.

Add DevFlow to a MAUI app. USE FOR: package refs, `MauiProgram` registration, Blazor WebView/GTK variants, verification after `maui devflow init`. DO NOT USE FOR: troubleshooting, debugging, UI inspection, or build failures. INVOKES: `maui devflow`, `dotnet`.

Analyze dotnet/maui PR failures across maui-pr, maui-pr-devicetests, and maui-pr-uitests against the latest five completed runs on the PR's target branch. Report only whether failures are PR-related, with failure links grouped by pipeline. When no current…

Common safety and triage protocol for .NET MAUI CI-fixer workflows. Use whenever investigating, creating, or advancing a `[ci-fix]` or `[ci-fix-net11]` pull request from direct CI evidence or a legacy `ci-scan` issue, including frozen ownership snapshots,…

Detects potential regression risks in a PR by cross-referencing lines the PR REMOVES against lines ADDED by recent labeled bug-fix PRs (`i/regression`, `t/bug`, `p/0`, `p/1`) touching the same files. Purely mechanical — no AI/LLM. Emits a CLEAN / OVERLAP /…

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).

Full manual-label policy for the maintainer-only /issue triage command in dotnet/maui. Assess issue type, area, platform, status, regression, priority, performance, ownership, versions, workarounds and planning against existing evidence. Do not use for the…

Trace a reported dotnet/maui issue to the commit or PR that introduced its regression using release boundaries, source history, and linked evidence. Use for "/issue trace-regression", "which PR introduced this issue", or "trace this regression". Distinguish…

Queries and triages open GitHub issues that need attention. Helps identify issues needing milestones, labels, or investigation.

Interpret pinned managed benchmark evidence for the /review performance GitHub Agentic Workflow. Produce a narrative for independently validated reporting; never execute measurements or publish directly.

Guidance for writing and reviewing SIMD / hardware-intrinsics code in dotnet/runtime. USE FOR: vectorizing a scalar algorithm, writing or reviewing code that uses Vector128/Vector256/Vector512, the generic Vector type, or the platform intrinsics in…

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…

Run the TechEmpower ASP.NET Core benchmarks against a locally-built dotnet/runtime, either locally with an SDK overlay or on external infrastructure using Crank, to validate the end-to-end impact of a runtime change (e.g. sockets, io_uring, GC, JIT) under…

Generate breaking change documentation for merged dotnet/runtime PRs. USE FOR: creating breaking change docs, "document this breaking change", "write breaking change issue for PR #NNNNN", processing PRs labeled needs-breaking-change-doc-created. DO NOT USE…

Build and test dotnet/runtime locally. Covers the mandatory baseline build, per-component build and test commands, Windows/PowerShell equivalents, running individual tests, and troubleshooting. USE FOR: any build or test invocation in this repo, and before…

Analyze a concrete CI failure and draft a Known Build Error issue or update in dotnet/runtime. Publish only with explicit user authorization or scoped authorization from an executing workflow's documented publication contract. Use when a failure is…

Triage a dotnet/runtime GitHub issue with duplicate search, label check, reproduction, and ecosystem research, then recommend KEEP/CLOSE/NEEDS INFO. Use when asked to triage, evaluate, assess, or check a specific GitHub issue. Also use when asked "is this a…

Extract a standalone JIT regression test case from a given GitHub issue and save it under a JIT regression runner folder. USE FOR: creating JIT regression tests, extracting repro code from dotnet/runtime issues, "write a test for this JIT bug", "create a…

Review EF Core pull requests or local changes for concrete correctness, compatibility, performance, security, and test-coverage problems. Use when asked to review, critique, or check code changes before merge or submission.

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

Create or modify GitHub Actions workflows for CI, automation, or PR management. Use when asked to create, scaffold, add, extend, or fix a workflow (.yml file under .github/workflows/), including existing pull-request policy and comment automation.

Create and evaluate VS Code file-based instructions (.instructions.md files). Use when asked to create, scaffold, or add file-based instructions for Copilot. Generates scoped instructions and a paired Vally harness eval.

Create, review, or fix Agent Skills for GitHub Copilot. Use when asked to create, scaffold, improve, or repair a SKILL.md and its paired harness evaluation.

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

Implement and review EF Core query translation, projection visitors, split-query enumeration, and query regression tests. Use when changing query-pipeline code or choosing specification and provider coverage for a query regression.

Implementation details for EF Core scaffolding (reverse engineering). Use when changing ef dbcontext scaffold pipeline implementation, database schema reading, CSharpModelGenerator, or related classes.

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…

Guides struct-based COM interop in MSBuild using CsWin32 patterns. Consult when working with the generic ComScope type, ComClassFactory, IComIID, the IID.Get generic method, delegate* unmanaged vtables, CoCreateInstance, or manually defining COM interfaces…

Guides CsWin32 P/Invoke interop in MSBuild. Consult when working with the PInvoke class, Windows.Win32 namespaces, FEATURE_WINDOWSINTEROP, HANDLE/HMODULE/HRESULT types, the generic BufferScope type, replacing [DllImport] with CsWin32, or conditioning…

Guides performance optimization for MSBuild engine code. Consult when working on hot paths in evaluation or execution, reducing allocations, choosing collection types, handling strings efficiently, modifying Expander.cs or Evaluator.cs, using Span-based APIs…

Guides authoring of MSBuild errors, warnings, and diagnostic messages. Consult when adding new MSBxxxx codes, writing or modifying user-facing diagnostic text, deciding between error/warning/message severity, working with Strings.resx resource files,…

Guides changes to MSBuild binary log infrastructure. Consult when modifying BinaryLogger or BinaryLogReplayEventSource, adding new BuildEventArgs types, changing event serialization/deserialization, modifying ProjectImportsCollector, adjusting message…

Deploy locally-built MSBuild binaries into a Visual Studio installation for testing and debugging. Use when you need VS itself to use your local MSBuild changes, or when debugging MSBuild as invoked by 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…

Performs multi-agent, multi-model code review of F# compiler PRs across 16 dimensions including type checking, IL emission, and binary compatibility. Dispatches parallel assessment agents per dimension, consolidates with cross-model agreement scoring, and…

Routes a Visual Studio integration or compiler-service review to the file for that tree. Use when reviewing a PR, pre-merge change, or edit under vsintegration, FSharp.Editor, the legacy language service, FSI, the project system, MEF, src/Compiler/Service,…

Write per-PR changelog entries for completed F# changes, or draft and review F# release announcements and articles for .NET preview, RC, and stable milestones.

Use when reviewing a PR where duplicated mechanisms, misplaced responsibilities, or competing fixes suggest a substantial design alternative rather than local corrections. Not for isolated bugs, style preferences, or size alone.

Use when about to defer useful work — when you catch yourself writing "follow-up", "future work", "out of scope", "v2", "next phase", "tracked in #NNN", "left as a TODO", "known limitation", or proposing to file an issue instead of finishing. Forces a binary…

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 /…

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.

Write a postmortem for a regression that escaped to production, broke real users, and traces back to a design flaw worth documenting for future implementors. Only invoke after confirming no existing postmortem or doc covers the same root cause.

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`…

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…

Generate `features.json` from `changes.json` by ranking and annotating shipped changes. `features.json` keeps the same schema as `changes.json` and adds optional scoring fields so release notes, docs, and blog posts can apply different cutoffs. Uses the…

Review `features.json` scores and draft release notes against the editorial examples and the shared `editorial-scoring` rubric. Use it to identify over-scored, under-scored, or missing features before publishing release notes. DO NOT USE FOR: generating…

Validate every release-note feature and its code snippets against the milestone build, and identify preview-to-preview migration steps when updating maintained samples. Reads the exact SDK version from build-metadata.json and installs it in a scoped location…

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…

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

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

Analyze existing memory dumps of Visual Studio (devenv.exe), its background process DevHub, or Roslyn language server processes for Roslyn memory retention. Use when investigating memory leaks, excessive memory usage, counting Solution or compilation objects,…

Update expected IL baselines in compiler unit tests from Actual output for tests that are explicitly reported as failed. Use when Test Explorer or test output shows IL baseline differences and the requested fix is limited to those failed tests.

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,…

Assess whether task-relevant agent documentation needs 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.

Analyze VMR codeflow PR status for dotnet repositories. Use when investigating stale codeflow PRs, checking if fixes have flowed through the VMR pipeline, debugging dependency update issues in PRs authored by dotnet-maestro[bot], checking overall flow status…

Investigate Visual Studio integration test failures from Azure DevOps builds. Use when investigating integration test timeouts, crashes, or failures in the roslyn-integration-CI pipeline. Also use when asked "why are integration tests failing", "integration…

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,…

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…

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…

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.

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…

Investigate .NET CI failures using the hlx CLI tool via bash. USE FOR: checking Helix job status, searching build logs, downloading test results, AzDO build timeline analysis — when MCP tools aren't loaded or when scripting with JSON output and jq. This is…

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…

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…

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 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…

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…

Query Maestro/BAR dependency flow data using the mstro CLI tool via bash. USE FOR: subscription health checks, build flow tracing, codeflow status, channel discovery, triggering subscription updates — when MCP tools aren't loaded or when scripting with JSON…