The Claude Code & Codex Skills Guidebook
53 agent skills tested in both tools
Skip the trial and error. 53 agent skills picked and run in Claude Code and Codex, each with who it fits, install commands, and a first run.
About
About the Book
There are thousands of agent skills on GitHub, and most come with a short README written for developers. Finding out whether one fits your work means installing it, running it, and cleaning up when it does not.
This guidebook does that sorting for you. It picks 53 skills worth your time across business, marketing, data analysis, design, development, operations, agent workflows, and vibe coding, and runs each one in both Claude Code and Codex.
Every skill chapter gives you the same five things, in the same order:
- Who it fits: situations rated good, okay, or poor fit, with a reason for each
- Install: the commands for Claude Code and for Codex
- First run: what to type and what the skill does step by step
- What makes it useful, and what to watch out for
- Sources: repository, license, and the files quoted
Foundation chapters explain agents, skills, subagents, MCP, and hooks in plain language, show how the two tools read the same SKILL.md, and walk you through sharing one skill folder between them. A roadmap by role (planning, design, development, marketing, operations, research) tells you which skills to read first.
Who it is for: developers, indie hackers, and solo founders who use Claude Code or Codex and want to stop writing the same instructions every session.
The book already has readers in Korean. The Korean edition went up free on Wikidocs (wikidocs.net/book/21365) in September 2026. AI curator @lucas_flatwhite, who has more than 15,000 followers on X, recommended it without being asked, and the official Wikidocs account shared it next. That month it reached #3 on the Wikidocs weekly ranking, with more than 12,000 views in one week. This is the English edition of that book.
About 280 pages. Reference versions: Claude Code v2.1.273 and Codex v0.153.4.
PDF and EPUB. Pay what you want from $19 (suggested $29). You get every future edition free: both tools change fast, and the book is revised as they do. Leanpub refunds 100% within 60 days.
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All packages include the ebook in the following formats: PDF and EPUB
The Book
Minimum price
Suggested price$29.00$19.00
Book + Author's Skill Pack
Minimum price
Suggested price$59.00The full book plus the author's own skills, ready to install: 20 skills, a six-agent ops team (sales, marketing, content, consulting, analysis, development), 6 more Claude Code subagents, and one installer for Claude Code and Codex. Also includes the Claude Code Setup Blueprint template and a worked sample, and the 10-minute checklist. Licensed for personal and internal use.
$49.00
- Author's Skill Pack: 20 skills, 6-agent ops team, 6 subagents, installer
- Claude Code Setup Blueprint: worked sample
- Claude Code Setup Blueprint: template
- 10-minute checklist
Author
About the Author
Jay Jung Lim is the founder of BuildnWrite, a Seoul company that coaches teams to build their own AI agents. Since 2023 Jay has run corporate AI training and agent coaching for more than 20 organizations. Jay coauthored "n8n Does It All" (Hanbit Media, 2026), teaches an 18-part Claude video course on Hanbit+ (hanbit.co.kr/product/C2240643131), and is a co-instructor on two free Inflearn courses with more than 1,300 learners combined as of October 2026 (inflearn.com/course/n8n-introductory-lec, inflearn.com/challenge/6-week-course-n8n-do). Jay uses 70 skills in daily work and has logged 6,275 Claude sessions and 1,048 Codex sessions working with agents. LinkedIn: linkedin.com/in/jayjunglim
Contents
Table of Contents
- About this book
- How to read this book
- 53 recommended skills
- Getting started with Claude Code and Codex
- What is an agent and where do skills fit
- What are agent skills
- Claude Code skills
- Codex skills
- Spec differences
- One folder for both tools
- Glossary
- Part 01 Business (7 skills)
- Part 02 Marketing (7 skills)
- Part 03 Data analysis (5 skills)
- Part 04 Design (7 skills)
- Part 05 Development (6 skills)
- Part 06 Operations (7 skills)
- Part 07 Working with agents (8 skills)
- Part 08 Vibe coding (6 skills)
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