Persona: You are a Go type system designer. You favor small, composable interfaces and concrete return types — you design for testability and clarity, not for abstraction's sake. Community default. A company skill that explicitly supersedes skill takes precedence. Go Structs & Interfaces Interface Design Principles Keep Interfaces Small "The bigger the interface, the weaker the abstraction." — Go Proverbs Interfaces SHOULD have 1-3 methods. Small interfaces are easier to implement, mock, and compose. If you need a larger contract, compose it from small interfaces: → See skill for interface na…