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No Fabricated Numbers — A Six-Month Field Manual for Claude Code, Prompts, Validation, and Production Memory
A 24-year game design veteran's field manual for putting generative AI to work in real production — with every prompt, every line of code, and every verification step disclosed.
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About the Book
A hands-on field manual by a game designer with 24 years in the industry on bringing generative AI (Claude Code) into daily production work. Not theory or forecasts — it walks one task at a time from the very first screen (install, accounts, pricing) through systems design, combat, narrative, level design, balance, UX, and live ops, all the way to turning meeting notes into decisions, validation gates, cost management, and copyright.
The subtitle — "No Fabricated Numbers" — is this book's promise. Every figure and case in the text comes from real work, not invented examples, and most of the code runs as is on the Python standard library alone.
The book is open to readers outside games, too. Workflows like turning meeting notes into decisions, tracing a decision's ripple effects, and guarding quality with validation gates work regardless of your job. The "Beyond Games" box in each chapter is the bridge, and every chapter also carries a "Solo Scale-Down" for people building alone, with no team.
AI will not replace a game designer's job. What it does is free your hands from the busywork. What you do with those hands is still up to you — and this book is the practical guide to that transition.
24 parts, appendices A-N, and an epilogue. With 185 diagrams and some 290 tables, it aims to be a book that gets your hands moving today — not one you read and put down.
This is the English edition of the Korean original (BOOKK, 2026 · ISBN 979-11-12-21479-9), translated with the book's own AI workflow and reviewed by the author.
About the Author
Minsoo Lee (이민수) started in games in 2002 with QA on the overseas edition of the PC RPG Arcturus, which led him to design work on Ragnarok Online — and he has been making games for 24 years since. He has moved between new development and live operations of MMORPGs, from R2 Online and Bless to MIR4 live ops, and has shipped a mobile roguelike along the way. He currently serves as design director on an MMORPG project.
He has always been a "designer who builds tools." He wrote damage simulators in VBA and made them the baseline for balancing; on large-scale projects he took on PM duties and derived update plans from production-throughput simulations. Before ChatGPT even existed, he wired the GPT-3 API into Google Sheets and ran a pipeline that auto-generated monster lore and quest drafts in production. To him, generative AI is not a trend but an old work tool.
Over the past six months he brought Claude Code into production and built his team's operating system around 304 rules and 48 tools — and that operating record became his book, AI Workflow for Game Designers.
At home, he builds small games alone. The same system running at both work and play — that, too, is what his book wants to say.
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