dotnet-best-practices-mh

name	dotnet-best-practices-mh
description	Apply practical, repository-aligned .NET/C# engineering practices without forcing framework-specific or architecture-specific choices.

.NET/C# Best Practices (Neutral Baseline)

Your goal is to help produce maintainable, production-ready .NET code while respecting the repository’s existing conventions and technology choices.

Core Rule

• Follow the repository’s established conventions first.
• If conventions are unclear, prefer standard modern .NET practices.
• Avoid introducing new frameworks, patterns, or architecture unless requested.

Scope and Change Discipline

• Keep changes focused and minimal for the requested outcome.
• Reuse existing abstractions before creating new ones.
• Do not change target framework, SDK version, or global project structure unless explicitly asked.
• Do not edit generated files.

API and Design

• Use clear names and cohesive methods.
• Prefer the least required visibility (private > internal > protected > public).
• Validate inputs at boundaries.
• Throw precise exceptions with actionable messages.
• Prefer composition and simple designs over speculative abstractions.

Async and Reliability

• Use async for I/O-bound work end-to-end.
• Avoid blocking async calls (.Result, .Wait()).
• Propagate CancellationToken where appropriate.
• Add timeouts and retries only where they are operationally justified.

Configuration and Observability

• Prefer strongly-typed configuration and validate required settings.
• Use structured logging with useful context.
• Avoid logging secrets or sensitive data.
• Preserve existing telemetry/logging patterns in the repository.

Security and Data Handling

• Validate and sanitize untrusted input.
• Use parameterized data access patterns.
• Apply least-privilege principles for credentials and access.
• Keep secrets out of source code and logs.

Testing Guidance (Framework-Neutral)

• Follow the testing framework already used by the solution.
• Add or update tests for changed behaviour, especially public-facing behaviour.
• Prefer deterministic tests that run independently.
• Use clear Arrange-Act-Assert structure.
• Mock only external dependencies when necessary.

Documentation

• Document non-obvious behaviour and important design decisions.
• For public APIs, add or maintain XML docs where the repository expects them.
• Keep comments focused on intent and rationale, not restating code.

Performance

• Prefer simple, readable implementations first.
• Optimize only when justified by measured evidence.
• Avoid unnecessary allocations in hot paths when practical.
• Stream large payloads when possible instead of buffering entire content.

Decision Priority

When guidance conflicts, use this order:

1. User request
2. Repository conventions
3. This skill
4. General .NET defaults