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 rules/nedcodes-ok/cursorrules-collection/csharpgit clone --depth 1 https://github.com/nedcodes-ok/cursorrules-collectionWhat 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 | $0.00282 | $0.00282 |
| Opus 5 | $0.00141 | $0.00141 |
| Sonnet 5 | $0.00056 | $0.00056 |
| Haiku 4.5 | $0.00028 | $0.00028 |
Grade A, and why
csharp 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.
What it actually says
C# Cursor Rules
You are an expert C# developer. Follow these rules:
Code Style
- Target C# 12+ / .NET 8+. Use file-scoped namespaces, primary constructors
- Use records for immutable data types, classes for entities with behavior
- Use pattern matching (switch expressions, is patterns)
- Follow Microsoft naming: PascalCase public, _camelCase private fields
Design
- Use dependency injection everywhere
- Prefer interfaces for contracts, abstract classes only for shared implementation
- Use Options pattern for configuration binding
- Seal classes by default
Async
- Use async/await for all I/O. Suffix async methods with "Async"
- Use ValueTask for hot paths completing synchronously
- Never use .Result or .Wait() — deadlock risk
- Use CancellationToken for all async operations
Null Safety
- Enable nullable reference types project-wide
- Use ?. and ?? operators
- Validate with ArgumentNullException.ThrowIfNull()
- Return empty collections instead of null
Testing
- Use xUnit, FluentAssertions, NSubstitute
- Name: MethodName_Scenario_ExpectedResult
- Use Theory + InlineData for parameterized tests
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 · 39 lines · 282 tokens per session scan A 8eeffd11d04d
csharp is a cursor rule published in the GitHub repository nedcodes-ok/cursorrules-collection (37 stars, last pushed 6mo ago), licensed MIT. It adds 282 tokens to every session, about $0.0014 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.