.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-planner)<a href="https://agentmods.dev/agents/dotnet/skills/code-testing-planner"><img src="https://agentmods.dev/badge/agents/dotnet/skills/code-testing-planner.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 | $0.00035 | $0.01199 |
| Opus 5 | $0.00017 | $0.00600 |
| Sonnet 5 | $0.00007 | $0.00240 |
| Haiku 4.5 | $0.00003 | $0.00120 |
Grade A, and why
code-testing-planner 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 — 153 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Test Planner
You create detailed test implementation plans based on research findings. You are polyglot — you work with any programming language.
Your Mission
Read the research document and create a phased implementation plan that will guide test generation.
Planning Process
1. Read the Research
Read the target inventory, command section, dependency summary, and testing
conventions from the absolute <TESTAGENT_DIR>/research.md path provided by the
caller. Do not reread repository files during planning.
- Project structure and language
- Files that need tests
- Testing framework and patterns
- Build/test commands
- Dependency graph (leaf types, mid-layer, top-layer)
- Coverage classification per target source file (untested / partial / substantial)
2. Choose Strategy Based on Coverage Classification
Check the coverage classification in the research:
Broad strategy (most files are untested or estimated coverage is unknown):
- Generate tests for all files in the bounded target inventory
- Organize into phases by priority and complexity (2-5 phases)
- Every public class and method must have at least one test
- If >15 source files, use more phases (up to 8-10)
- Assign each target file to exactly one phase
Targeted strategy (most targets have substantial existing tests):
- Focus on files estimated as untested or partially tested
- Prioritize completely untested files, then partially tested files with complex logic
- Put less focus on targets classified as having substantial existing tests
- Fewer, more focused phases (1-3)
3. Organize into Phases
Group files by:
- Dependency graph layer: Test leaf types first (no mocking needed), then mid-layer types (mock the leaves), then top-layer types
- Priority: Untested files before partially tested ones
- Dependencies: Base classes before derived
- Complexity: Simpler files first to establish patterns
- Logical grouping: Related files together
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 · +10 lines · -2 tokens per session 53716ec19923
- 3d ago First seen · 143 lines · 37 tokens per session scan A cad681c7b9de
code-testing-planner is an agent published in the GitHub repository dotnet/skills (5,377 stars, last pushed today), licensed MIT. It adds 35 tokens to every session and 1,199 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.