Guide · Agent skill
How to use the C# .NET Developer agent skill (csharp-developer)
Updated · written with AI from the project's own documentation and checked against our catalogue data
The csharp-developer skill is a set of instructions and reference notes that teaches an AI agent to work the way a senior C# and .NET developer would. It targets .NET 8+ projects, including ASP.NET Core APIs, Entity Framework Core data access and Blazor web apps. This guide explains what the skill changes, how to install it, how to ask for help so the agent uses it, and what to check before you trust the output.
C# .NET DeveloperJeffallan/claude-skills · MIT Download the skill Quick start
- 1Download the ZIP. Get the csharp-developer skill ZIP from this page.
- 2Unzip into a skills folder. Extract it into ~/.claude/skills/ for personal use, or into a project's .claude/skills/ folder.
- 3Or upload it in the Claude apps. Go to Settings → Capabilities → Skills and upload the ZIP.
- 4Install the .NET 8+ SDK. Make sure the dotnet CLI is available so the EF Core migration commands can run.
- 5Ask a specific C# request. Describe the API, EF Core change or Blazor component you need and name the technology.
- 6Review the output. Read the code, check the migration file and run your tests before merging.
What is an agent skill?
An agent skill is a folder containing a SKILL.md file and optional reference files. When you install a skill, an AI agent that supports skills can read it and load its guidance when a request matches the skill's description.
The csharp-developer skill's description tells the agent to use it when you are building C# applications with .NET 8+, ASP.NET Core APIs, or Blazor web apps.
What the skill makes the agent do
Once installed, the agent follows established .NET patterns when it writes code for these areas. According to the skill's instructions, it builds REST APIs with minimal or controller-based routing, configures database access with Entity Framework Core, implements async patterns and cancellation, structures applications with CQRS via MediatR, and scaffolds Blazor components with state management.
The skill also sets defaults the agent should follow: enable nullable reference types, accept and forward CancellationToken in async I/O code, use dependency injection, map EF Core entities to DTOs instead of returning them from APIs, use IOptions<T> for configuration, and use a Result pattern for errors. It avoids blocking calls such as .Result and .Wait().
- Minimal API and controller-based endpoints
- Entity Framework Core queries and migrations, with a review checkpoint
- Blazor components with parameters and state
- Async code with cancellation tokens
- Result<T> error handling and DTO mapping
Install the csharp-developer skill
Download the skill ZIP from this page and unzip it. The skill folder should contain SKILL.md and the references folder.
For a personal install that works across your projects, unzip it into ~/.claude/skills/. To limit it to one project, unzip it into that project's .claude/skills/ folder.
In the Claude apps, you can instead upload the ZIP under Settings → Capabilities → Skills.
Trigger the skill with natural requests
You do not need a special command. Describe a C# or .NET task in plain language and name the technology, using the trigger words listed in the skill: C#, .NET, ASP.NET Core, Blazor, Entity Framework, EF Core, Minimal API, MAUI, SignalR.
Be specific about the project. Mention the .NET version, whether you want Minimal APIs or controllers, and which database layer you use.
- Create a Minimal API in .NET 8 with endpoints for listing and fetching products, using async methods and cancellation tokens.
- Add an EF Core entity configuration for Order and generate a migration.
- Build a Blazor Server component that lists customers and loads them asynchronously.
Review EF Core migrations before applying them
The skill includes a checkpoint after the implementation step. It asks the agent to run dotnet ef migrations add <Name>, then review the generated migration file before applying it, confirming there are no unintended table or column drops. If the migration is wrong, the skill suggests dotnet ef migrations remove to roll it back.
This needs the .NET 8+ SDK (dotnet CLI) and the Entity Framework Core tools (dotnet ef) installed on your machine.
dotnet ef migrations add <Name>Safety notes: scripts and network
According to the skill's listing, it does not run scripts and does not use the network. It is a set of instructions and reference documents, so the agent's work happens through the tools you already allow in your environment.
The skill is not a substitute for testing. The generated code must be built, tested and reviewed by a person before it reaches production.
What people use it for
- Scaffolding a .NET 8 Minimal API with route groups, DTOs and cancellation tokens
- Adding an Entity Framework Core configuration and reviewing a generated migration
- Building a Blazor component with loading states and parameters
- Refactoring a controller to use async methods that accept CancellationToken
Frequently asked questions
How do I install the csharp-developer skill?
Download the ZIP from this page and unzip it into ~/.claude/skills/ for personal use, or into a project's .claude/skills/ folder. In the Claude apps, you can upload the ZIP under Settings → Capabilities → Skills.
What do I need to use the csharp-developer skill?
The skill's listing says you need the .NET 8+ SDK with the dotnet CLI for the EF Core migration commands, and the Entity Framework Core tools (dotnet ef) if you generate migrations. It runs no scripts and uses no network.
Is the csharp-developer skill free?
The skill is released under the MIT licence, as stated on this page. The licence terms are the authority on what you can do with it.
Does the skill work with projects that are not .NET?
No. The guidance is for C# and .NET projects. For other languages, the skill's patterns will not apply.
Can I use this skill instead of reviewing code?
No. The skill produces code that must be tested and checked by a person, especially for production use and database migrations.
What if my team has its own architecture rules?
The skill defaults to CQRS with MediatR and the Result pattern. If these conflict with your team's internal architecture rules, the skill may not fit well and you should adjust the instructions or choose another approach.
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Our verdict
Choose this skill if you build or maintain .NET 8+ web APIs, Entity Framework Core data layers or Blazor apps and want an agent that follows consistent senior-level patterns. Skip it if you are not a developer, if your project does not use .NET, or if your team's architecture rules conflict with its CQRS/MediatR and Result-pattern defaults.
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