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Guide · Agent skill

How to use the .NET Core Expert agent skill

Updated · written with AI from the project's own documentation and checked against our catalogue data

The dotnet-core-expert skill is a set of instructions and reference notes that an AI agent loads when you ask it to build a .NET 8 backend. It steers the agent toward minimal API endpoints, layered clean architecture with CQRS via MediatR, Entity Framework Core data access, JWT authentication and cloud-ready setup. This guide shows you how to install it, how to trigger it with plain requests, and what to check before you trust the output.

.NET Core ExpertJeffallan/claude-skills · MIT

Quick start

  1. 1Download the ZIP. Get the dotnet-core-expert skill ZIP from this page.
  2. 2Unzip into a skills folder. Unzip into ~/.claude/skills/ for all projects, or into the project's .claude/skills/ for one project.
  3. 3Or upload in the Claude apps. In the Claude apps, go to Settings → Capabilities → Skills and upload the ZIP.
  4. 4Confirm prerequisites. Make sure the .NET 8 SDK is installed and, if you use data access, Entity Framework Core and a database provider are set up.
  5. 5Make a specific request. Describe the .NET 8 service you want, naming the entities, endpoints and whether you need a database or authentication.
  6. 6Review the build and tests. Check that dotnet build and dotnet test pass on your machine and read the generated code before using it.

What an agent skill is and what this one makes the agent do

An agent skill is a folder containing a SKILL.md file and optional reference files. When the skill matches your request, the agent reads those notes and follows them while it works. This skill is written for backend implementation in C# on .NET 8.

Its core workflow asks the agent to analyse requirements, design layers, implement, add security, and test. During implementation it runs dotnet build and fixes errors before continuing. During testing it runs dotnet test and checks endpoints with curl or a REST client.

  • Uses minimal APIs, with endpoints mapped in Program.cs
  • Separates Domain, Application, Infrastructure and WebApi layers
  • Uses MediatR handlers for CQRS queries and commands
  • Uses async/await for I/O, record types for DTOs, and nullable reference types
  • Avoids returning raw entities from APIs and adds input validation
  • Writes xUnit tests and integration tests with WebApplicationFactory<Program>

Install the dotnet-core-expert skill

Download the skill ZIP from the page you are reading. Then choose one of two routes depending on how you use your agent.

For Claude Code, unzip the folder into ~/.claude/skills/ to make it available everywhere, or into a project's .claude/skills/ folder to make it available only in that project. For the Claude apps, upload the ZIP under Settings → Capabilities → Skills.

  • Personal install: unzip into ~/.claude/skills/
  • Project install: unzip into the project's .claude/skills/ folder
  • Claude apps: Settings → Capabilities → Skills, then upload the ZIP

Check the prerequisites before you start

The skill assumes you have the .NET 8 SDK installed, because the workflow calls dotnet build and dotnet test. If the project uses data access, you also need Entity Framework Core and a database provider. The guidance also references MediatR, xUnit and the WebApplicationFactory package. For endpoint checks, you need curl or a REST client.

Set up your project file as the skill expects. The guidance asks for nullable reference types to be enabled in the .csproj.

  • .NET 8 SDK (required for dotnet build and dotnet test)
  • Entity Framework Core and a database provider, if you use data access
  • MediatR, xUnit and WebApplicationFactory packages, as referenced by the guidance
  • curl or a REST client for endpoint checks
<Nullable>enable</Nullable>

Trigger the skill with natural requests

You do not need a special command. Describe the backend you want and mention .NET 8 or one of the skill's topics. The description matches requests about minimal APIs, clean architecture, cloud-native microservices, Entity Framework Core, CQRS with MediatR, JWT authentication and AOT compilation.

The more specific your request, the better the output. Name the entity, the endpoints you need and whether you want a database.

  • Build a .NET 8 minimal API for managing products with EF Core and a SQL database.
  • Create a clean architecture solution with CQRS and MediatR for an orders service.
  • Add JWT authentication to my ASP.NET Core API and protect the admin endpoints.
  • Set up a Dockerfile and health checks for my .NET 8 microservice.

Example: a minimal API endpoint with MediatR

The skill's reference examples show the typical shape of the output. A minimal endpoint sends a query through ISender and returns NotFound or Ok. The handler reads with AsNoTracking and projects to a record DTO, so no entity leaves the data layer.

Expect the agent to produce files like these, along with the project structure and a short note on its architectural choices.

app.MapGet("/users/{id}", async (int id, ISender sender, CancellationToken ct) => { var result = await sender.Send(new GetUserQuery(id), ct); return result is null ? Results.NotFound() : Results.Ok(result); }) .WithName("GetUser") .Produces<UserDto>() .ProducesProblem(404);

Safety notes: scripts and network

This skill runs scripts. The agent is directed to run dotnet build, dotnet test and curl on your machine, so review what it runs, especially if you use it unattended. The skill does not use the network itself, but the commands it runs, such as restores, can reach outside sources as part of normal .NET tooling.

The skill does not audit the code it writes. It tells the agent to add authentication and validation, but a human should review auth, validation and data access before anything reaches production.

  • Runs scripts: yes (dotnet build, dotnet test, curl)
  • Uses network: no, according to the skill's listing
  • Review generated auth, validation and database code before production use
  • Do not expect unattended runs to be safe without supervision

Tips for better results

Ask for one slice at a time, such as a single endpoint with its handler and tests. Smaller requests are easier to review and easier for the agent to get building. If a build or test fails, let the agent read the errors, since the workflow tells it to fix and rerun.

Ask for the layers you want explicitly. If you already use MediatR, EF Core and JWT, say so, so the agent matches your existing style rather than introducing new patterns.

  • Name the framework version and the packages you already use
  • Request tests alongside each endpoint
  • Ask the agent to explain its architectural decisions, which the output template expects
  • Check the project builds and tests pass on your own machine

What people use it for

  • Starting a new .NET 8 Web API with minimal endpoints and Swagger/OpenAPI documentation
  • Adding CQRS queries and commands with MediatR to an existing layered solution
  • Adding JWT authentication and authorization policies to an ASP.NET Core API
  • Writing a Dockerfile and health checks for a .NET 8 microservice
  • Learning clean architecture in C# through worked examples the agent produces

Frequently asked questions

How do I install the dotnet-core-expert skill?

Download the skill ZIP from this page. Unzip it into ~/.claude/skills/ for personal use, or into a project's .claude/skills/ folder for one project. In the Claude apps, upload the ZIP under Settings → Capabilities → Skills.

What do I need to run it?

You need the .NET 8 SDK, because the workflow calls dotnet build and dotnet test. If you use data access, add Entity Framework Core and a database provider. You also need curl or a REST client for endpoint checks.

Is the dotnet-core-expert skill free?

The skill is listed under the MIT licence. The licence terms are on the source repository, so check them there if you plan to reuse or modify the files.

Does it work with languages other than C#?

No. It covers C# and .NET 8 patterns only. For non-.NET projects, the advice will be for the wrong stack, so pick a skill built for your language.

Does the skill run code on my computer?

Yes. The skill is listed as running scripts, and its workflow directs the agent to run dotnet build, dotnet test and curl. Review those commands, especially if you let the agent work unattended.

Is the code it generates secure enough for production?

The skill tells the agent to add authentication, authorization and input validation, but it does not audit the result. Have a developer review the auth, validation and data access code before it goes to production.

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Our verdict

Use this skill if you are building a .NET 8 Web API or microservice and want an agent to follow modern minimal API, CQRS and EF Core patterns consistently. Pick something else if your project is not .NET, if you need a security audit of the output, or if you want an agent that runs commands without supervision.

Download the skill