agent-rules-books is a collection of Markdown rules and skills that guide AI coding agents using principles from books on software design, refactoring, architecture, domain-driven design, reliability, and data systems. Developers use the rules with Codex, Cursor, Claude Code, and other compatible agents to shape how they perform coding tasks. The catalogue skills package these rule sets for installation and use by coding agents.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add ciembor/agent-rules-books --skill refactoring-gurugit clone --depth 1 https://github.com/ciembor/agent-rules-booksWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/ciembor/agent-rules-books/refactoring-guru)<a href="https://agentmods.dev/skills/ciembor/agent-rules-books/refactoring-guru"><img src="https://agentmods.dev/badge/skills/ciembor/agent-rules-books/refactoring-guru/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/ciembor/agent-rules-books/refactoring-guru"><img src="https://agentmods.dev/badge/skills/ciembor/agent-rules-books/refactoring-guru.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00029 | $0.00137 |
| Opus 5 | $0.00015 | $0.00068 |
| Sonnet 5 | $0.00006 | $0.00027 |
| Haiku 4.5 | $0.00003 | $0.00014 |
Grade A, and why
refactoring-guru scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Refactoring.Guru Skill
Use this skill when a task involves diagnosing smells, choosing targeted refactoring treatments, preserving behavior, applying a refactoring catalog, or avoiding uncontrolled redesign.
Before making design or code decisions, read and apply refactoring-guru.mini.md. Use refactoring-guru.md only as a deeper reference when the mini rules are not enough for the current refactoring tradeoff.
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- today First seen · 12 lines · 29 tokens per session scan A 66c509c4c997
refactoring-guru is a skill published in the GitHub repository ciembor/agent-rules-books (2,731 stars, last pushed today), licensed MIT. It adds 29 tokens to every session and 137 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-09.
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