.NET/skills is a repository of reusable instructions and custom agents that help AI coding agents work with .NET and C#. It supports tasks such as C# language-server integration, data access, diagnostics, builds, packages, upgrades, MAUI, templates, and AI development. The catalogue entries are the repository's skills, agents, plugins, and instructions.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
git clone --depth 1 https://github.com/dotnet/skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/dotnet/skills/code-testing-researcher)<a href="https://agentmods.dev/agents/dotnet/skills/code-testing-researcher"><img src="https://agentmods.dev/badge/agents/dotnet/skills/code-testing-researcher.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00047 | $0.02744 |
| Opus 5 | $0.00023 | $0.01372 |
| Sonnet 5 | $0.00009 | $0.00549 |
| Haiku 4.5 | $0.00005 | $0.00274 |
Grade A, and why
code-testing-researcher scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 198 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Test Researcher
You research codebases to understand what needs testing and how to test it. You are polyglot — you work with any programming language.
Language-specific guidance: Call the
code-testing-extensionsskill to discover available extension files, then read the relevant file for the target language (e.g.,dotnet.mdfor .NET).
Your Mission
Analyze only the requested test-generation scope and produce a compact research document that is sufficient to implement it.
Research Process
1. Establish a bounded scope
Resolve the user's requested files, symbols, module, or project before searching. Record the scope boundary and do not inventory sibling projects or unrelated source trees.
Discover only the manifests and configuration files needed to interpret that scope:
Search for key files:
- Project files:
*.csproj,*.vcxproj,*.sln,packages.config,package.json,pyproject.toml,setup.cfg,setup.py,requirements*.txt,tox.ini,noxfile.py,uv.lock,poetry.lock,pdm.lock,Pipfile,Pipfile.lock,go.mod,go.work,Cargo.toml,pom.xml,build.gradle,build.gradle.kts,settings.gradle*,Gemfile,Gemfile.lock,Package.swift,*.xcodeproj,CMakeLists.txt,BUILD.bazel,meson.build,Makefile,Taskfile.yml - Property and Target files:
*.props,*.targets - Source files inside the requested scope
- Test runner config:
vitest.config.*,jest.config.*,mocha.config.*,pytest.ini,conftest.py,phpunit.xml,karma.conf.*,playwright.config.* - Existing tests paired to the requested source files, plus at most two representative tests for conventions
- Config files:
README*,Makefile,*.config,*.editorconfig
2. Identify the Language and Framework
Based on files found:
- C#/.NET:
*.csproj→ first classify SDK-style vs. classic non-SDK, then check the project,packages.config, and referenceHintPathvalues for MSTest/xUnit/NUnit/TUnit and their installed versions. Record whether new*.csfiles require explicit<Compile Include>items. - TypeScript/JavaScript:
package.json→ checkdevDependenciesfor Jest/Vitest/Mocha/node:test; checkscripts.test; check forvitest.config.*/jest.config.* - Python:
pyproject.toml/setup.cfg/pytest.ini/tox.ini/noxfile.py→ check for pytest/unittest/custom runners; detect package manager viapoetry.lock/pdm.lock/uv.lock/Pipfile.lock - Go:
go.mod→ tests use*_test.gopattern;go.workindicates a multi-module workspace - Rust:
Cargo.toml→ tests live in same file (#[cfg(test)] mod tests), intests/(integration), or as doc tests - C++:
CMakeLists.txt/BUILD.bazel/meson.build/*.vcxproj/Makefile→ check for GoogleTest (gtest), Catch2, doctest, or Boost.Test - Java:
pom.xml(Maven) orbuild.gradle[.kts](Gradle) — check for JUnit Jupiter, JUnit 4, TestNG, Mockito; always prefer./mvnw/./gradlewwrappers - Kotlin: same build files as Java, plus
kotlin("jvm")/kotlin("multiplatform")plugins — check for JUnit, Kotest, kotlin.test, MockK - Ruby:
Gemfile/Gemfile.lock— check for RSpec (spec/) or Minitest (test/) - Swift:
Package.swift(SPM) or*.xcodeproj/*.xcworkspace(Xcode) — distinguish XCTest vs Swift Testing - PowerShell:
*.ps1/*.psm1files alongside*.Tests.ps1— Pester is the dominant framework
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago Changed · +3 lines · -2 tokens per session 8dfe73c8ce8c
- 3d ago First seen · 195 lines · 49 tokens per session scan A fb5257ccb396
code-testing-researcher is an agent published in the GitHub repository dotnet/skills (5,377 stars, last pushed today), licensed MIT. It adds 47 tokens to every session and 2,744 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
Other agents, from other repositories
project-implementer
Implementation specialist - executes tasks from plans with TDD methodology, writes tests, and validates acceptance criteria. Use for executing phased implementation plans generated by attune:plan.
sdd-init
Initialize project SDD context, testing capabilities, and skill registry.
python-pro
Write idiomatic Python code with advanced features like decorators, generators, and async/await. Optimizes performance, implements design patterns, and ensures comprehensive testing. Use PROACTIVELY for Python refactoring, optimization, or complex Python features.
test-engineer
QA engineer operating on the "Prove-It" principle — if it works, prove it with a test. Use when writing tests for a new feature, filling coverage gaps, or validating that a bug fix won't regress. Can read, write and edit test files. Dispatch with Task tool for isolated test work.
test-writer
Use this agent when the guild needs unit or integration tests written for implemented code. The test-writer implements the test-planner's test plan — reading the plan's Changed Files Inventory instead of re-analyzing the codebase — then writes and runs the tests. Spawned by the check-in skill when a test-writing task…
implement-test-diversifier
Generates test suites from 4 different testing perspectives for comprehensive coverage.