dotnet-csharp

name	dotnet-csharp
description	Guides C# language patterns, coding standards, and .NET runtime features including async/await, dependency injection, configuration, source generators, nullable reference types, serialization, channels, LINQ optimization, domain modeling, SOLID principles, concurrency, analyzers, editorconfig, file I/O, native interop, validation, modern C# syntax (records, pattern matching, primary constructors), and API design.
license	MIT
user-invocable	false

dotnet-csharp

Overview

C# language patterns, coding standards, and .NET runtime features for idiomatic, performant code. This consolidated skill spans 22 topic areas. Load the appropriate companion file from references/ based on the routing table below.

Baseline dependency: references/coding-standards.md defines naming, file layout, and style rules that apply to all C# code generation and review tasks. Load it by default whenever C# code will be produced.

Most-shared companion: references/async-patterns.md is referenced by 4 agents and covers async/await patterns critical to nearly all .NET development.

Routing Table

Topic	Keywords	Description	Companion File
Coding standards	naming, file layout, style rules	Baseline C# conventions (naming, layout, style rules)	references/coding-standards.md
Async/await	async, Task, ConfigureAwait, cancellation	async/await, Task patterns, ConfigureAwait, cancellation	references/async-patterns.md
Dependency injection	DI, services, scopes, keyed, lifetimes	MS DI, keyed services, scopes, decoration, lifetimes	references/dependency-injection.md
Configuration	Options pattern, user secrets, feature flags	Options pattern, user secrets, feature flags, IOptions<T>	references/configuration.md
Source generators	IIncrementalGenerator, GeneratedRegex, LoggerMessage	IIncrementalGenerator, GeneratedRegex, LoggerMessage, STJ	references/source-generators.md
Nullable reference types	annotations, migration, agent mistakes	Annotation strategies, migration, agent mistakes	references/nullable-reference-types.md
Serialization	System.Text.Json, Protobuf, MessagePack, AOT	System.Text.Json source generators, Protobuf, MessagePack	references/serialization.md
Channels	Channel<T>, bounded/unbounded, backpressure	Channel<T>, bounded/unbounded, backpressure, drain	references/channels.md
LINQ optimization	IQueryable vs IEnumerable, compiled queries	IQueryable vs IEnumerable, compiled queries, allocations	references/linq-optimization.md
Domain modeling	aggregates, value objects, domain events	Aggregates, value objects, domain events, repositories	references/domain-modeling.md
SOLID principles	SRP, DRY, anti-patterns, compliance checks	SOLID and DRY principles, C# anti-patterns, fixes	references/solid-principles.md
Concurrency	lock, SemaphoreSlim, Interlocked, concurrent collections	lock, SemaphoreSlim, Interlocked, concurrent collections	references/concurrency-patterns.md
Roslyn analyzers	DiagnosticAnalyzer, CodeFixProvider, multi-version	DiagnosticAnalyzer, CodeFixProvider, CodeRefactoring	references/roslyn-analyzers.md
Editorconfig	IDE/CA severity, AnalysisLevel, globalconfig	IDE/CA severity, AnalysisLevel, globalconfig, enforcement	references/editorconfig.md
File I/O	FileStream, RandomAccess, FileSystemWatcher, paths	FileStream, RandomAccess, FileSystemWatcher, MemoryMappedFile	references/file-io.md
Native interop	P/Invoke, LibraryImport, marshalling	P/Invoke, LibraryImport, marshalling, cross-platform	references/native-interop.md
Input validation	.NET 10 AddValidation, FluentValidation	.NET 10 AddValidation, FluentValidation, ProblemDetails	references/input-validation.md
Validation patterns	DataAnnotations, IValidatableObject, IValidateOptions	DataAnnotations, IValidatableObject, IValidateOptions<T>	references/validation-patterns.md
Modern patterns	records, pattern matching, primary constructors	Records, pattern matching, primary constructors, C# 12-15	references/modern-patterns.md
API design	naming, parameter ordering, return types, extensions	Naming, parameter ordering, return types, error patterns	references/api-design.md
Type design/perf	struct vs class, sealed, Span/Memory, collections	struct vs class, sealed, Span/Memory, collections	references/type-design-performance.md
Code smells	anti-patterns, async misuse, DI mistakes, fixes	Anti-patterns, async misuse, DI mistakes, fixes	references/code-smells.md

Scope

• C# language features (C# 8-15)
• .NET runtime patterns (async, DI, config, serialization, channels, LINQ)
• Code quality (analyzers, editorconfig, code smells, SOLID)
• Type design and domain modeling
• File I/O and native interop
• Input validation (model and options validation)

Out of scope

• ASP.NET Core / web API patterns -> [skill:dotnet-api]
• UI framework patterns -> [skill:dotnet-ui]
• Testing patterns -> [skill:dotnet-testing]
• Build/MSBuild/project setup -> [skill:dotnet-tooling]
• Performance profiling tools -> [skill:dotnet-tooling]