Claude Code for C# Source Generators Workflow

C# source generators have transformed how .NET developers write code, enabling compile-time code generation that eliminates boilerplate and enhances productivity. However, developing and debugging source generators can be challenging without the right workflow. This guide shows you how to use Claude Code to streamline your source generator development process, from initial setup through debugging and optimization.

Understanding Source Generators in Your Project

Source generators run during compilation and can inspect your code to generate additional source files automatically. They’re particularly powerful for reducing boilerplate in scenarios like JSON serialization, dependency injection registration, and API client generation. When working with source generators, Claude Code can help you understand existing implementations, debug generation issues, and implement new generators efficiently.

Before diving into workflow specifics, ensure your development environment includes the .NET SDK and an editor with Roslyn support. Visual Studio Code with the C# extension or JetBrains Rider both provide excellent source generator debugging capabilities. Claude Code interacts with these tools through your terminal, making it compatible with any editor setup.

Setting Up Your Source Generator Project

A well-structured source generator project follows specific conventions that Claude Code can help you establish. The typical project structure includes a main library project consuming the generator and a separate generator project referencing Microsoft.CodeAnalysis.CSharp.

// GeneratorProject.csproj
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
    <LangVersion>latest</LangVersion>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.8.0" />
  </ItemGroup>
</Project>

When setting up your generator, use the ISourceGenerator interface alongside GeneratorInitializationContext for registering syntax receivers. Claude Code can generate starter templates for common generator patterns, saving you time on initial setup.

Developing Generators with Claude Code Assistance

The development workflow benefits significantly from AI-assisted code generation and explanation. When implementing a source generator, you’ll work with the Roslyn API to analyze syntax trees, find attributes or patterns, and emit generated code.

Analyzing Syntax Nodes

Your generator implements the Execute method to traverse the compilation’s syntax trees. Here’s a practical pattern for finding classes with specific attributes:

public void Execute(GeneratorExecutionContext context)
{
    var syntaxReceiver = (SyntaxReceiver)context.SyntaxReceiver;
    
    foreach (var classDeclaration in syntaxReceiver.CandidateClasses)
    {
        var semanticModel = context.Compilation.GetSemanticModel(classDeclaration.SyntaxTree);
        var classSymbol = semanticModel.GetDeclaredSymbol(classDeclaration);
        
        // Check for target attribute and generate code
        if (classSymbol.HasAttribute(attributeSymbol))
        {
            var generatedCode = GenerateCode(classSymbol);
            context.AddSource($"{classSymbol.Name}.generated.cs", generatedCode);
        }
    }
}

Claude Code helps you understand how to navigate the Roslyn API, explaining the relationship between syntax nodes and semantic symbols. When you encounter compilation errors in generated code, describe the error message and context—Claude Code often identifies common issues like namespace conflicts or missing using statements.

Writing the Generated Code

Generating syntactically correct C# code requires careful string construction or using code generation APIs. The SourceGeneratorPak library simplifies this by providing type-safe code generation through fluent APIs.

public string GenerateCode(INamedTypeSymbol classSymbol)
{
    var sb = new StringBuilder();
    sb.AppendLine("using System;");
    sb.AppendLine($"namespace {classSymbol.ContainingNamespace}");
    sb.AppendLine("{");
    sb.AppendLine($"    public partial class {classSymbol.Name}");
    sb.AppendLine("    {");
    sb.AppendLine($"        public string GeneratedProperty => \"Value\";");
    sb.AppendLine("    }");
    sb.AppendLine("}");
    return sb.ToString();
}

Claude Code can review your generation logic for potential issues, suggest improvements to reduce code duplication in generated output, and help you implement incremental generation for better performance.

Debugging Source Generator Issues

Debugging source generators requires a different approach than regular debugging since generated code isn’t visible in your source files. The debugging workflow involves examining generated output and understanding the generator’s execution context.

Viewing Generated Output

Visual Studio provides a “Diagnostic Tools” window showing generated files during compilation. In VS Code, you can inspect generated files in the obj folder under Generated_Sources. Claude Code can guide you through locating and examining these files when generation produces unexpected results.

When debugging, start by checking whether the syntax receiver correctly identifies target nodes. Add diagnostic reporting during development to understand what the generator observes:

context.ReportDiagnostic(Diagnostic.Create(
    new DiagnosticDescriptor("SG001", "Debug", 
        "Analyzing {0} at {1}", "Category", 
        DiagnosticSeverity.Info, true),
    classDeclaration.GetLocation(),
    classSymbol.Name,
    classDeclaration.SpanStart));

Common Pitfalls and Solutions

Several common issues plague source generator development. Infinite recursion occurs when generated code triggers regeneration—you solve this by using IncrementalGenerator APIs that track changes effectively. Missing dependencies happen when generated code references types not yet available during generation—ensure your generator project has all necessary type references.

Performance problems arise from regenerating unnecessarily. Implement the IIncrementalGenerator interface and configure pipeline steps that skip regeneration when inputs haven’t changed:

public void Initialize(IncrementalGeneratorInitializationContext context)
{
    var classProvider = context.SyntaxProvider
        .ForAttributeWithMetadataName("MyAttribute")
        .Select((ctx, _) => ctx.TargetSymbol);
    
    context.RegisterSourceOutput(classProvider, GenerateCode);
}

Claude Code helps you identify which pattern applies to your situation and provides implementation guidance specific to your use case.

Optimizing Your Development Workflow

Beyond core development, several practices improve your source generator workflow efficiency. Version your generated APIs using source anchors to enable proper debugging across generated file boundaries. Write comprehensive tests using snapshot testing frameworks that compare generated output against expected files.

When collaborating with team members, document generator behavior and configuration options clearly. Claude Code can help you generate documentation from your generator’s attribute definitions and configuration classes.

Best Practices for Production Generators

Moving generators to production requires attention to error handling, diagnostics, and performance. Always provide meaningful diagnostic messages when generation fails. Use incremental generation to maintain fast build times even with complex generators. Test generators against diverse input scenarios including edge cases.

Version your generator following semantic versioning, as breaking changes in generated code affect downstream consumers. Consider providing migration guides when making significant changes to generated output patterns.

Conclusion

Integrating Claude Code into your C# source generator workflow accelerates development, improves code quality, and helps navigate the Roslyn API’s complexity. By following the practices outlined in this guide—structuring projects properly, using incremental generation, and implementing effective debugging—you’ll create robust source generators that enhance your .NET development experience.

The key to success lies in iterative development: start with simple generators, validate output, then progressively add complexity. Claude Code serves as an intelligent partner throughout this journey, helping you understand APIs, debug issues, and implement best practices efficiently.

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