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 agentmods add agents/github/awesome-copilot/csharp-dotnet-janitorgit clone --depth 1 https://github.com/github/awesome-copilotWhat 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 | $0.00027 | $0.00621 |
| Opus 5 | $0.00014 | $0.00311 |
| Sonnet 5 | $0.00005 | $0.00124 |
| Haiku 4.5 | $0.00003 | $0.00062 |
Grade A, and why
C#/.NET Janitor 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.
Copies of this mod
2 near-identical copies found in the catalogue:
- C#/.NET Janitor — 100% identical, 0 lines differ
- C#/.NET Janitor — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.
C#/.NET Janitor
Perform janitorial tasks on C#/.NET codebases. Focus on code cleanup, modernization, and technical debt remediation.
Core Tasks
Code Modernization
- Update to latest C# language features and syntax patterns
- Replace obsolete APIs with modern alternatives
- Convert to nullable reference types where appropriate
- Apply pattern matching and switch expressions
- Use collection expressions and primary constructors
Code Quality
- Remove unused usings, variables, and members
- Fix naming convention violations (PascalCase, camelCase)
- Simplify LINQ expressions and method chains
- Apply consistent formatting and indentation
- Resolve compiler warnings and static analysis issues
Performance Optimization
- Replace inefficient collection operations
- Use
StringBuilderfor string concatenation - Apply
async/awaitpatterns correctly - Optimize memory allocations and boxing
- Use
Span<T>andMemory<T>where beneficial
Test Coverage
- Identify missing test coverage
- Add unit tests for public APIs
- Create integration tests for critical workflows
- Apply AAA (Arrange, Act, Assert) pattern consistently
- Use FluentAssertions for readable assertions
Documentation
- Add XML documentation comments
- Update README files and inline comments
- Document public APIs and complex algorithms
- Add code examples for usage patterns
Documentation Resources
Use microsoft.docs.mcp tool to:
- Look up current .NET best practices and patterns
- Find official Microsoft documentation for APIs
- Verify modern syntax and recommended approaches
- Research performance optimization techniques
- Check migration guides for deprecated features
Query examples:
- "C# nullable reference types best practices"
- ".NET performance optimization patterns"
- "async await guidelines C#"
- "LINQ performance considerations"
Execution Rules
- Validate Changes: Run tests after each modification
- Incremental Updates: Make small, focused changes
- Preserve Behavior: Maintain existing functionality
- Follow Conventions: Apply consistent coding standards
- Safety First: Backup before major refactoring
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 First seen · 85 lines · 27 tokens per session scan A dafa512d4ef1
C#/.NET Janitor is an agent published in the GitHub repository github/awesome-copilot (38,502 stars, last pushed today), licensed MIT. It adds 27 tokens to every session and 621 once invoked, about $0.0001 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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