Agent Skills: writing-flows

Writes single-scenario Flow documents under flows/<topic>/ — use case context, one Mermaid diagram (sequence or flowchart), step-by-step branches, and source file references — so how a service behaves end-to-end can be grasped at a glance. Use when user asks for a sequence diagram, user flow, use case doc, or mentions 시퀀스 다이어그램, 유저 플로우, 플로우 그려줘, 동작 흐름, 플로우 작성. Also trigger on intent like 어떻게 동작하는지 한눈에 보고 싶다, 동작 순서 정리해줘 — but not on simple code questions about a single function.