Code Comprehension
Evidence-based readability and cognitive-load review of code. Use when asked to "review this for readability", "is this too complex", "reduce nesting or cognitive load", "what is a reasonable method length / parameter count / nesting depth", or when judging whether code will be hard to understand. Screens code against research-backed thresholds and prioritizes the factors that actually drive comp…
Agent Files Review
Review changes to AI-agent customization files (AGENTS.md, .github/copilot-instructions.md, *.instructions.md, *.prompt.md, *.agent.md, SKILL.md, the validator, the CI workflow). Use when asked to review or validate agent-file changes, fix CI failures from the agent-files workflow, or audit a draft of any of these files.
Create Pr
Create a pull request for the current changes. Use when asked to "make a PR", "open a pull request", "push and PR", or otherwise publish in-progress work for review. Ensures changes are on a non-`main` branch, commits are made and pushed, and the PR targets `upstream/main` when an `upstream` remote exists, otherwise `origin/main`.
Scratch Buffer Strategy
Choose how a hot path gets a short-lived scratch buffer - zeroed `stackalloc`, `[SkipLocalsInit]` + `stackalloc`, `BufferScope` of T (stack with pool fallback), or a rental from the shared `ArrayPool` of T - and apply the net481/net10 size crossovers. Use when designing or reviewing a performance-sensitive path that needs a temporary buffer, when deciding "should I rent or stackalloc?", when weig…
Framework Jit Optimization
Optimize hot-path code for the `net481` (.NET Framework) target in a multi-targeted library's Framework-only sources. Use when writing or reviewing performance-sensitive loops, deciding whether to specialize a generic method for primitive types, choosing between scalar/unrolled/BCL-delegating implementations, or diagnosing why a net481 micro-benchmark regresses on the older RyuJIT. Also covers th…
Performance Testing
Author and run BenchmarkDotNet performance tests in a multi-targeted .NET library's perf project, and translate a user's outcome-shaped performance question into a measurement. Use when adding new benchmarks, running existing ones, comparing implementations, profiling to find which method or source line dominates, evaluating allocations / memory usage, reading the generated code (sharplab / Disas…
Engineering Baseline
Create a new .NET repository fully wired for building, testing, and publishing with OSS best practices, or bring an existing repository up to a documented engineering baseline. Use when asked to "create a new repository" / "scaffold a new project" (a CLI tool, a class library / NuGet package, or a multi-target library) with CI, packaging, branch protection, and governance files, or to "ensure thi…
Il Copy Inspection
Find struct value copies in a method's compiled IL - defensive copies, boxing, by-value field/argument/return copies - by reading the emitted bytecode rather than predicting from source. Use when asked to "find struct copies", "where does the compiler copy this struct", "is this a defensive copy", "check for boxing in IL", "did the compiler emit a copy here", "confirm the analyzer's defensive-cop…
Roslyn Analyzers
Design, build, validate, and ship a Roslyn analyzer (and optional code fix) in a dedicated analyzer project. Use when asked to "write an analyzer", "create a Roslyn/diagnostic analyzer", "add an analyzer rule", "add a code fix", "enforce a convention at build time", or "flag a pattern in code". ALWAYS starts by checking whether an existing analyzer suite (the .NET SDK CA/IDE rules, BannedApiAnaly…
Pre Pr Self Review
Self-review checklist - plus an agentic review pass (a read-only reviewer persona over the diff) - before opening a PR. Use before invoking `create-pr`, when reviewing your own draft, or when a reviewer flags issues that should have been caught earlier. Codifies recurring mistakes from multi-targeted polyfill work - missing tests for new public surface, unchecked length sums, null-pointer foot-gu…
Fuzz Testing
Author and run SharpFuzz coverage-guided fuzz targets for a .NET library. Use when adding a new fuzz target, running the fuzzer locally, installing the fuzzing prerequisites, or promoting a crashing input into a regression test. Covers the cross-TFM harness, the libFuzzer driver workflow, and the crash-to-regression loop.
Dotnet Polyfills
Set up and use the standard .NET downlevel polyfill stack so a multi-targeted library can call modern BCL APIs on .NET Framework - PolySharp for compiler and language attributes, the official Microsoft downlevel NuGet packages (System.Memory, Microsoft.Bcl.Memory, Microsoft.Bcl.HashCode, Microsoft.IO.Redist, and the other Microsoft.Bcl.* / System.* backports), and the KlutzyNinja.Touki package's…
Security Review
Security-focused review of pending changes. Audit any change that could affect safety or correctness under abusive input or unchecked preconditions - oversized values, malformed structures, integer/length overflow, catastrophic backtracking, allocation pressure, other denial-of-service shapes, and any use of `unsafe` code or the `Unsafe` / `MemoryMarshal` / `Marshal` static helpers (which trade c…
Address Pr Feedback
Address feedback on an existing pull request - review comments, requested changes, CI failures, or any post-PR follow-up work. Use when the user says "address the review", "fix the comments", "address Copilot's feedback", "fix the CI failure", or any similar phrasing. Distinct from `create-pr`, which covers opening the *initial* PR.
Manage Skills
Find, add, update, and share agent skills in this repo. Use when asked to "find a skill" for a task, "build a skill" or "create a skill" (this skill checks whether one already exists - in the repo, the shared commons, or a public catalog - before authoring a new one), "update a skill", or reconcile a local skill change against the upstream commons vs a repo-local overlay. Covers the find-first bu…
Github Actions Cost Optimization
Audit and reduce GitHub Actions runner usage and normalized cost without weakening required validation. Use when asked to reduce CI cost, spend, minutes, or job count; optimize workflow triggers, matrices, runner selection, caches, or artifact retention; eliminate duplicate Actions runs; or decide which checks should be automatic versus scheduled or manual. Not for application runtime performance…