How does this skill help with NuGet package maintenance?

It provides standardized patterns for versioning, safe signature changes, and deprecation workflows using the [Obsolete] attribute to guide users through migration without breaking their builds.

What is extend-only design in C#?

Extend-only design is a philosophy where public APIs are never modified or removed once released. Instead, functionality is added through new overloads or types, ensuring existing code remains functional during upgrades.

Can this skill detect breaking changes during code reviews?

Yes, it integrates strategies for API Approval Testing using tools like PublicApiGenerator, which creates a text-based snapshot of your API surface that must be explicitly approved if changed.

What is the difference between source and wire compatibility?

Source compatibility ensures code compiles against a new version, while wire compatibility ensures serialized data (like JSON or Protobuf) can be read by different versions of a distributed system.

C# API Design & Compatibility

Name: C# API Design & Compatibility
Author: Aaronontheweb

byAaronontheweb

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API Development

Implements extend-only design principles to build stable, backward-compatible C# APIs and distributed systems.

This skill provides specialized guidance for .NET developers on maintaining public API stability using 'extend-only' design principles. It enables Claude to assist in designing NuGet packages, managing binary and wire compatibility for distributed systems, and implementing automated API surface testing. By focusing on immutable functionality and structured deprecation patterns, it ensures that library upgrades remain non-breaking for end-users while allowing for the continuous evolution of features. It is particularly useful for maintainers of high-traffic open-source libraries and enterprise-grade distributed architectures.

Key Features

01423 GitHub stars

02Extend-only design pattern implementation for C# libraries

03Validation of source, binary, and wire compatibility

04Safe deprecation and versioning strategies for NuGet packages

05Automated API surface testing setup using ApiApprover and Verify

06Guidelines for evolving wire formats in distributed systems

Use Cases

01Designing and maintaining public-facing NuGet packages with stable contracts

02Reviewing pull requests to detect and prevent accidental breaking changes

03Planning zero-downtime upgrades for distributed systems via wire-compatible evolution

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add aaronontheweb/dotnet-skills csharp-api-design

For use in Claude.ai and ChatGPT

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