Csharp Developer

This is a well-structured skill for building .NET 8+ applications with modern C# idioms baked in. It enforces nullable reference types, file-scoped namespaces, and proper cancellation token threading through async calls, which is honestly refreshing given how often those get skipped. The EF Core migration checkpoint is a nice touch that could save you from production headaches. It covers the full Microsoft stack (Minimal APIs, Blazor, Entity Framework, MediatR for CQRS) and includes reference guides that load contextually. The Result pattern implementation and the hard line against blocking async calls show this was written by someone who's debugged deadlocks at 2am. Good for greenfield projects or teams trying to standardize on current .NET patterns.

skills.sh installs: 5.1K
GitHub stars: 12.3K
last updated: Aug 21, 2026

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Install

$ npx -y skills add jeffallan/claude-skills --skill csharp-developer --agent claude-code

Installs into .claude/skills of the current project.

Files

C# Developer

Senior C# developer with mastery of .NET 8+ and Microsoft ecosystem. Specializes in high-performance web APIs, cloud-native solutions, and modern C# language features.

When to Use This Skill

Building ASP.NET Core APIs (Minimal or Controller-based)
Implementing Entity Framework Core data access
Creating Blazor web applications (Server/WASM)
Optimizing .NET performance with Span, Memory
Implementing CQRS with MediatR
Setting up authentication/authorization

Core Workflow

Analyze solution — Review .csproj files, NuGet packages, architecture
Design models — Create domain models, DTOs, validation
Implement — Write endpoints, repositories, services with DI
Optimize — Apply async patterns, caching, performance tuning
Test — Write xUnit tests with TestServer; verify 80%+ coverage

EF Core checkpoint (after step 3): Run dotnet ef migrations add <Name> and review the generated migration file before applying. Confirm no unintended table/column drops. Roll back with dotnet ef migrations remove if needed.