McpServerAspNetCore: Instructions file for GitHub Copilot

General

• Make only high confidence suggestions when reviewing code changes.
• Always use the latest version C#, currently C# 14 features.
• Write code that is clean, maintainable, and easy to understand.
• Only add comments rarely to explain why a non-intuitive solution was used. The code should be self-explanatory otherwise.
• Don't add the UTF-8 BOM to files unless they have non-ASCII characters.
• Never change global.json unless explicitly asked to.
• Never change package.json or package-lock.json files unless explicitly asked to.
• Never change NuGet.config files unless explicitly asked to.

Code Style

Formatting

• Apply code-formatting style defined in .editorconfig.
• Use primary constructors where applicable.
• Prefer file-scoped namespace declarations and single-line using directives.
• Insert a newline before the opening curly brace of any code block (e.g., after if, for, while, foreach, using, try, etc.).
• Ensure that the final return statement of a method is on its own line.
• Use pattern matching and switch expressions wherever possible.
• Prefer using collection expressions when possible
• Use is pattern matching instead of as and null checks
• Use nameof instead of string literals when referring to member names.
• Prefer ?. if applicable (e.g. scope?.Dispose()).
• Use ObjectDisposedException.ThrowIf where applicable.
• Use ArgumentNullException.ThrowIfNull to validate input parameters.
• If you add new code files, ensure they are listed in the csproj file (if other files in that folder are listed there) so they build.

Nullable Reference Types

• Declare variables non-nullable, and check for null at entry points.
• Always use is null or is not null instead of == null or != null.
• Trust the C# null annotations and don't add null checks when the type system says a value cannot be null.

Architecture and Design Patterns

Asynchronous Programming

• Provide both synchronous and asynchronous versions of methods where appropriate.
• Use the Async suffix for asynchronous methods.
• Return Task or ValueTask from asynchronous methods.
• Use CancellationToken parameters to support cancellation.
• Avoid async void methods except for event handlers.
• Use ConfigureAwait(false) only in library code that may be consumed by apps with a SynchronizationContext (e.g., classic ASP.NET, WPF, WinForms); it is generally unnecessary in ASP.NET Core.