This skill should be used when the user asks "monolith vs microservices", how to "split into services", set "service boundaries", find the right "service granularity", design an "API gateway / BFF", do "service discovery" or add a "service mesh", or worries that services are "too chatty" / "too fine-grained". It gives the recipe for carving a system into services (or deciding not to) and wiring how they find and call each other. Use it whenever a design has more than one service — or someone is tempted to add more — even if the user doesn't say "microservices".
