Aaron Stannard built this for .NET developers who need to think carefully about public API surface area and versioning. It walks you through the three types of compatibility (binary, source, and wire format) and helps you catch breaking changes before they ship to NuGet. The skill shines during PR reviews and when you're planning migrations for distributed systems where wire format matters. It's opinionated in a good way, the kind of guidance that comes from shipping real libraries and dealing with the consequences of bad breaking changes. If you maintain anything with external consumers, this will save you from angry GitHub issues six months down the line.
npx skills add https://github.com/aaronontheweb/dotnet-skills --skill api-design