# C# Rules

For C# or .NET work, open only the topic rules relevant to the task. Follow repository conventions and load applicable shared security rules as well.

| Topic | Codex rule | Claude skill |
| --- | --- | --- |
| Language style and code organization | `references/coding-style.md` | `rules-csharp-coding-style` |
| Types, collections, and public contracts | `references/types-and-collections.md` | `rules-csharp-types-and-collections` |
| Architecture and API boundaries | `references/architecture-and-apis.md` | `rules-csharp-architecture-and-apis` |
| Async work and concurrency | `references/async-and-concurrency.md` | `rules-csharp-async-and-concurrency` |
| Performance | `references/performance.md` | `rules-csharp-performance` |
| Security | `references/security.md` | `rules-csharp-security` |
| Validation, errors, and logging | `references/safety-and-errors.md` | `rules-csharp-safety-and-errors` |
| Tests, dependencies, and analyzers | `references/testing-and-dependencies.md` | `rules-csharp-testing-and-dependencies` |