The problem

Brand marketers without developers or designers needed to build, publish and run roulette, scratch-card, quiz and stamp events — mobile-first and shared through KakaoTalk.

Decisions

1. The layout is never generated at runtime. People design and fix the archetype skeletons; the conversation fills in only color, tone, copy, assets and motion.
2. Published events are re-read on every render and the schema only grows — no injected defaults. Each change batch proves DOM, text and typesetting identical on 4 demos and 5 real samples.
3. Limited agent editing: it opens for 72 hours only when the customer asks, and covers copy only. Odds, stock and verification are excluded by a server whitelist; both sides are logged.

What broke — and the fix

1. A feature kept vanishing from production: the deploy script never checked the branch, so 17 main deploys overwrote another branch’s build. Merged, plus six deploy guards — branch, same commit as the remote, clean tree, post-deploy alias check and more.
2. Seven checks that always passed were caught and rebuilt with negative controls, which exposed six real product defects they had been hiding.

Results

• 25+ verification scripts, 1,700+ assertions
• Cost per free event ₩185 → about ₩60 (prompt caching + a lighter model)
• Three archetypes live; per-store signed QR stamps used in production
• 238 CC0 assets in the library
• Render identity for published events: SAME 9/9 × 3