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.
npx skills add PracticalSwan/agent-skills --skill dotnet-best-practicesgit clone --depth 1 https://github.com/PracticalSwan/agent-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/skills/practicalswan/agent-skills/dotnet-best-practices)<a href="https://agentmods.dev/skills/practicalswan/agent-skills/dotnet-best-practices"><img src="https://agentmods.dev/badge/skills/practicalswan/agent-skills/dotnet-best-practices/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/practicalswan/agent-skills/dotnet-best-practices"><img src="https://agentmods.dev/badge/skills/practicalswan/agent-skills/dotnet-best-practices.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Prompt Injection · line 142 Hidden instructions were detected in comments or invisible text. These could contain malicious directives. Manual review is recommended.Fix: Audit all comments and invisible characters. Remove any instructions that direct the agent to perform unauthorized actions. Use plain, reviewable content.
- medium Data Exfiltration · line 119 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
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 | $0.00043 | $0.01249 |
| Opus 5 | $0.00022 | $0.00624 |
| Sonnet 5 | $0.00009 | $0.00250 |
| Haiku 4.5 | $0.00004 | $0.00125 |
Grade A, and why
dotnet-best-practices 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 yesterday.
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 — 138 lines — stays where its author put it; the contents beside it link to each section on GitHub.
.NET/C# Best Practices
Your task is to ensure .NET/C# code in ${selection} meets the best practices specific to this solution/project. This includes:
Documentation & Structure
- Create comprehensive XML documentation comments for all public classes, interfaces, methods, and properties
- Include parameter descriptions and return value descriptions in XML comments
- Follow the established namespace structure: {Core|Console|App|Service}.{Feature}
Design Patterns & Architecture
- Use primary constructor syntax for dependency injection (e.g.,
public class MyClass(IDependency dependency)) - Implement the Command Handler pattern with generic base classes (e.g.,
CommandHandler<TOptions>) - Use interface segregation with clear naming conventions (prefix interfaces with 'I')
- Follow the Factory pattern for complex object creation.
Dependency Injection & Services
- Use constructor dependency injection with null checks via ArgumentNullException
- Register services with appropriate lifetimes (Singleton, Scoped, Transient)
- Use Microsoft.Extensions.DependencyInjection patterns
- Implement service interfaces for testability
Resource Management & Localization
- Use ResourceManager for localized messages and error strings
- Separate LogMessages and ErrorMessages resource files
- Access resources via
_resourceManager.GetString("MessageKey")
Async/Await Patterns
- Use async/await for all I/O operations and long-running tasks
- Return Task or Task from async methods
- Use ConfigureAwait(false) where appropriate
- Handle async exceptions properly
Testing Standards
- Use MSTest framework with FluentAssertions for assertions
- Follow AAA pattern (Arrange, Act, Assert)
- Use Moq for mocking dependencies
- Test both success and failure scenarios
- Include null parameter validation tests
Configuration & Settings
- Use strongly-typed configuration classes with data annotations
- Implement validation attributes (Required, NotEmptyOrWhitespace)
- Use IConfiguration binding for settings
- Support appsettings.json configuration files
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- yesterday Changed · -35 lines fa517f4df798
- 2d ago Changed 526387e9b328
- 5d ago Changed 8f921da6d2cc
- 9d ago First seen · 173 lines · 43 tokens per session scan A d0d90aecd0ee
dotnet-best-practices is a skill published in the GitHub repository PracticalSwan/agent-skills (13 stars, last pushed yesterday), licensed MIT. It adds 43 tokens to every session and 1,249 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 2026-08-30.
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