writing-hookify-rules

A skill for writing hookify rules, including guidance on their syntax and patterns.

In plain words
What is it for?
Use it when creating, configuring, or asking about hookify rules.
Why use it?
It helps you create correctly structured rules when you need to prevent a specific agent behaviour.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/fazxes/claude-code/writing-rules
Any agent
npx skills add fazxes/Claude-code --skill writing-rules
Clone the repo
git clone --depth 1 https://github.com/fazxes/Claude-code

Made for: Claude Code, Codex.

Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,255 The whole file, excluding the scripts and references it only reads on demand.
Security scan D 2 findings. Scan, not verified.
Origin unknown No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00052 $0.02255
Opus 5 $0.00026 $0.01128
Sonnet 5 $0.00010 $0.00451
Haiku 4.5 $0.00005 $0.00226

Measured 2d ago against content hash 2994b5d31522, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade D, and why

writing-hookify-rules scanned grade D with 2 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 2d ago.

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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

chmod\s+777 Matches: chmod 777, chmod 777

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

rm\s+-rf Matches: rm -rf, rm -rf
stubs/downloads/official-plugins/marketplaces/claude-plugins-official/plugins/hookify/skills/writing-rules/SKILL.md · 375 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Changes

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.

  1. 2d ago First seen · 375 lines · 52 tokens per session scan D 2994b5d31522

Subscribe to this mod's changes

writing-hookify-rules is a skill published in the GitHub repository fazxes/Claude-code (233 stars, last pushed 5mo ago), with no licence file. It adds 52 tokens to every session and 2,255 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it D with 2 findings (asks for root, recursive force delete). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.