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name: csharp-standards description: Modern C# 14 / .NET 10 coding standards and best practices. Based on CONSTITUTION. Use when writing or editing C# code. metadata: author: csharp-standards version: "4.0.0"

C# 14 / .NET 10 Coding Standards

Philosophy: Defensive Coding | Strict Analysis | Pragmatic DDD | Vertical Slices

Goal: Zero warnings, zero allocations on hot paths, type-safety, immutability.

Core Principles

1. Sealed by default — all classes sealed unless abstract
2. Internal by default — public only for library APIs
3. No null returns — use ErrorOr<T> or Option<T>
4. No exceptions for logic — Result pattern for expected failures
5. Value Objects — wrap primitives in domain types
6. Vertical slices — organize by features, not layers

References

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