csharp-developer

Name: csharp-developer
Author: Jeffallan

3.5kinstalls971forks

How to install csharp-developer?

jeffallan/claude-skills/csharp-developer

$npx -y skills add Jeffallan/claude-skills --skill csharp-developer

Installs into the current project.

Summary

Use when building C# applications with .NET 8+, ASP.NET Core APIs, or Blazor web apps. Builds REST APIs using minimal or controller-based routing, configures database access with Entity Framework Core, implements async patterns and cancellation, structures applications with CQRS

Files · 1

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SKILL.md

1	# C# Developer
2
3	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.
4
5	## When to Use This Skill
6
7	- Building ASP.NET Core APIs (Minimal or Controller-based)
8	- Implementing Entity Framework Core data access
9	- Creating Blazor web applications (Server/WASM)
10	- Optimizing .NET performance with Span<T>, Memory<T>
11	- Implementing CQRS with MediatR
12	- Setting up authentication/authorization
13
14	## Core Workflow
15
16	1. Analyze solution — Review .csproj files, NuGet packages, architecture
17	2. Design models — Create domain models, DTOs, validation
18	3. Implement — Write endpoints, repositories, services with DI
19	4. Optimize — Apply async patterns, caching, performance tuning
20	5. Test — Write xUnit tests with TestServer; verify 80%+ coverage
21
22	> 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.
23
24	## Reference Guide
25
26	Load detailed guidance based on context:
27
28	\| Topic \| Reference \| Load When \|
29	\|-------\|-----------\|-----------\|
30	\| Modern C# \| `references/modern-csharp.md` \| Records, pattern matching, nullable types \|
31	\| ASP.NET Core \| `references/aspnet-core.md` \| Minimal APIs, middleware, DI, routing \|
32	\| Entity Framework \| `references/entity-framework.md` \| EF Core, migrations, query optimization \|
33	\| Blazor \| `references/blazor.md` \| Components, state management, interop \|
34	\| Performance \| `references/performance.md` \| Span<T>, async, memory optimization, AOT \|
35
36	## Constraints
37
38	### MUST DO
39	- Enable nullable reference types in all projects
40	- Use file-scoped namespaces and primary constructors (C# 12)
41	- Apply async/await for all I/O operations — always accept and forward `CancellationToken`:
42	```csharp
43	// Correct
44	app.MapGet("/items/{id}", async (int id, IItemService svc, CancellationToken ct) =>
45	await svc.GetByIdAsync(id, ct) is { } item ? Results.Ok(item) : Results.NotFound());
46	```
47	- Use dependency injection for all services
48	- Include XML documentation for public APIs
49	- Implement proper error handling with Result pattern:
50	```csharp
51	public readonly record struct Result<T>(T? Value, string? Error, bool IsSuccess)
52	{
53	public static Result<T> Ok(T value) => new(value, null, true);
54	public static Result<T> Fail(string error) => new(default, error, false);
55	}
56	```
57	- Use strongly-typed configuration with `IOptions<T>`
58
59	### MUST NOT DO
60	- Use blocking calls (`.Result`, `.Wait()`) in async code:
61	```csharp
62	// Wrong — blocks thread and risks deadlock
63	var data = service.GetDataAsync().Result;
64
65	// Correct
66	var data = await service.GetDataAsync(ct);
67	```
68	- Disable nullable warnings without proper justification
69	- Skip cancellation token support in async methods
70	- Expose EF Core entities directly in API responses — always map to DTOs
71	- Use string-based configuration keys
72	- Skip input validation
73	- Ignore code analysis warnings
74
75	## Output Templates
76
77	When implementing .NET features, provide:
78	1. Domain models and DTOs
79	2. API endpoints (Minimal API or controllers)
80	3. Repository/service implementations
81	4. Configuration setup (Program.cs, appsettings.json)
82	5. Brief explanation of architectural decisions
83
84	## Example: Minimal API Endpoint
85
86	```csharp
87	// Program.cs (file-scoped, .NET 8 minimal API)
88	var builder = WebApplication.CreateBuilder(args);
89	builder.Services.AddScoped<IProductService, ProductService>();
90
91	var app = builder.Build();
92
93	app.MapGet("/products/{id:int}", async (
94	int id,
95	IProductService service,
96	CancellationToken ct) =>
97	{
98	var result = await service.GetByIdAsync(id, ct);
99	return result.IsSuccess ? Results.Ok(result.Value) : Results.NotFound(result.Error);
100	})
101	.WithName("GetProduct")
102	.Produces<ProductDto>()
103	.ProducesProblem(404);
104
105	app.Run();
106	```
107
108	## Knowledge Reference
109
110	C# 12, .NET 8, ASP.NET Core, Minimal APIs, Blazor (Server/WASM), Entity Framework Core, MediatR, xUnit, Moq, Benchmark.NET, SignalR, gRPC, Azure SDK, Polly, FluentValidation, Serilog
111
112	[Documentation](https://jeffal

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6 picks

Type

csharp-developer

3.5kinstalls971forks

View on GitHub

How to install csharp-developer?

jeffallan/claude-skills/csharp-developer

$npx -y skills add Jeffallan/claude-skills --skill csharp-developer

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# C# Developer
2
3	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.
4
5	## When to Use This Skill
6
7	- Building ASP.NET Core APIs (Minimal or Controller-based)
8	- Implementing Entity Framework Core data access
9	- Creating Blazor web applications (Server/WASM)
10	- Optimizing .NET performance with Span<T>, Memory<T>
11	- Implementing CQRS with MediatR
12	- Setting up authentication/authorization
13
14	## Core Workflow
15
16	1. Analyze solution — Review .csproj files, NuGet packages, architecture
17	2. Design models — Create domain models, DTOs, validation
18	3. Implement — Write endpoints, repositories, services with DI
19	4. Optimize — Apply async patterns, caching, performance tuning
20	5. Test — Write xUnit tests with TestServer; verify 80%+ coverage
21
22	> 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.
23
24	## Reference Guide
25
26	Load detailed guidance based on context:
27
28	\| Topic \| Reference \| Load When \|
29	\|-------\|-----------\|-----------\|
30	\| Modern C# \| `references/modern-csharp.md` \| Records, pattern matching, nullable types \|
31	\| ASP.NET Core \| `references/aspnet-core.md` \| Minimal APIs, middleware, DI, routing \|
32	\| Entity Framework \| `references/entity-framework.md` \| EF Core, migrations, query optimization \|
33	\| Blazor \| `references/blazor.md` \| Components, state management, interop \|
34	\| Performance \| `references/performance.md` \| Span<T>, async, memory optimization, AOT \|
35
36	## Constraints
37
38	### MUST DO
39	- Enable nullable reference types in all projects
40	- Use file-scoped namespaces and primary constructors (C# 12)
41	- Apply async/await for all I/O operations — always accept and forward `CancellationToken`:
42	```csharp
43	// Correct
44	app.MapGet("/items/{id}", async (int id, IItemService svc, CancellationToken ct) =>
45	await svc.GetByIdAsync(id, ct) is { } item ? Results.Ok(item) : Results.NotFound());
46	```
47	- Use dependency injection for all services
48	- Include XML documentation for public APIs
49	- Implement proper error handling with Result pattern:
50	```csharp
51	public readonly record struct Result<T>(T? Value, string? Error, bool IsSuccess)
52	{
53	public static Result<T> Ok(T value) => new(value, null, true);
54	public static Result<T> Fail(string error) => new(default, error, false);
55	}
56	```
57	- Use strongly-typed configuration with `IOptions<T>`
58
59	### MUST NOT DO
60	- Use blocking calls (`.Result`, `.Wait()`) in async code:
61	```csharp
62	// Wrong — blocks thread and risks deadlock
63	var data = service.GetDataAsync().Result;
64
65	// Correct
66	var data = await service.GetDataAsync(ct);
67	```
68	- Disable nullable warnings without proper justification
69	- Skip cancellation token support in async methods
70	- Expose EF Core entities directly in API responses — always map to DTOs
71	- Use string-based configuration keys
72	- Skip input validation
73	- Ignore code analysis warnings
74
75	## Output Templates
76
77	When implementing .NET features, provide:
78	1. Domain models and DTOs
79	2. API endpoints (Minimal API or controllers)
80	3. Repository/service implementations
81	4. Configuration setup (Program.cs, appsettings.json)
82	5. Brief explanation of architectural decisions
83
84	## Example: Minimal API Endpoint
85
86	```csharp
87	// Program.cs (file-scoped, .NET 8 minimal API)
88	var builder = WebApplication.CreateBuilder(args);
89	builder.Services.AddScoped<IProductService, ProductService>();
90
91	var app = builder.Build();
92
93	app.MapGet("/products/{id:int}", async (
94	int id,
95	IProductService service,
96	CancellationToken ct) =>
97	{
98	var result = await service.GetByIdAsync(id, ct);
99	return result.IsSuccess ? Results.Ok(result.Value) : Results.NotFound(result.Error);
100	})
101	.WithName("GetProduct")
102	.Produces<ProductDto>()
103	.ProducesProblem(404);
104
105	app.Run();
106	```
107
108	## Knowledge Reference
109
110	C# 12, .NET 8, ASP.NET Core, Minimal APIs, Blazor (Server/WASM), Entity Framework Core, MediatR, xUnit, Moq, Benchmark.NET, SignalR, gRPC, Azure SDK, Polly, FluentValidation, Serilog
111
112	[Documentation](https://jeffal

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6 picks

Type