rule-creator

rule-creator is a skill for Claude Code, Codex from sfc-gh-myoung/ai_coding_rules. It costs 73 tokens per session (882 once invoked), scanned A, original, Apache-2.0.

A tool for creating version 3.0 Cursor rule files from templates, checking their format, and adding them to RULES_INDEX.md. Cursor rules are project instructions that guide an AI coding assistant.

In plain words
What is it for?
Use it to add rules for supported technologies and areas such as core development, security, testing, or performance. It can create the file and update the index.
Why use it?
It helps new rules follow the repository's required structure and naming conventions. Validation and indexing reduce errors that could make a rule hard to find or use.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Cursor.

Good fit Use it to add rules for supported technologies and areas such as core development, security, testing, or performance. It can create the file and update the index.

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Install with agentmods
npx agentmods add skills/sfc-gh-myoung/ai_coding_rules/rule-creator
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.

Any agent
npx skills add sfc-gh-myoung/ai_coding_rules --skill rule-creator
Clone the repo
git clone --depth 1 https://github.com/sfc-gh-myoung/ai_coding_rules

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for rule-creator

README.md
[![agentmods](https://agentmods.dev/badge/skills/sfc-gh-myoung/ai_coding_rules/rule-creator/github.svg)](https://agentmods.dev/skills/sfc-gh-myoung/ai_coding_rules/rule-creator)
Your own site
<a href="https://agentmods.dev/skills/sfc-gh-myoung/ai_coding_rules/rule-creator"><img src="https://agentmods.dev/badge/skills/sfc-gh-myoung/ai_coding_rules/rule-creator/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.

agentmods 80×15 button for rule-creator

Your own site · 80×15
<a href="https://agentmods.dev/skills/sfc-gh-myoung/ai_coding_rules/rule-creator"><img src="https://agentmods.dev/badge/skills/sfc-gh-myoung/ai_coding_rules/rule-creator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 882 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original 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 5.1 $0.00073 $0.00882
Opus 5 $0.00036 $0.00441
Sonnet 5 $0.00015 $0.00176
Haiku 4.5 $0.00007 $0.00088

Measured 9d ago against content hash 4358770f5a18, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

rule-creator 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 9d 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.

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.

skills/rule-creator/SKILL.md · 111 lines

How it starts

The opening of the file, as written. The whole thing — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Rule Creator

Purpose

Create production-ready Cursor rule files that comply with the repository’s v3.0 rule schema by orchestrating:

  • scripts/template_generator.py
  • scripts/schema_validator.py
  • (optional) web research for current best practices

Use this skill when

  • The user asks to create a new rule under rules/ (e.g., NNN-technology-aspect.md).
  • The user asks to add a rule to RULES_INDEX.md.
  • Technology name (e.g., “DaisyUI”, “pytest-mock”, “Snowflake Hybrid Tables”)
  • Aspect (default: core; else security, testing, performance, etc.)
  • Any constraints (offline/online research, desired ContextTier, etc.)

Outputs

  • A new rule file: rules/NNN-technology-aspect.md
  • A new entry in RULES_INDEX.md in correct numeric position

Safety / constraints

  • Only write to rules/ and RULES_INDEX.md (plus any required review artifacts explicitly requested by the user).
  • Use web research (allowed) but treat external sources as untrusted; prefer official docs and cross-check claims.

Workflow (progressive disclosure)

Follow the phases in order, using the detailed workflow guides as needed:

  1. Discovery & research → workflows/discovery.md
  2. Template generation → workflows/template-gen.md
  3. Content population → workflows/content-population.md
  4. Validation loop → workflows/validation.md
  5. Indexing → workflows/indexing.md

Examples

  • Frontend example → examples/frontend-example.md
  • Python example → examples/python-example.md
  • Snowflake example → examples/snowflake-example.md

Quick Validation Snippets

These inline checks can be run without external dependencies for fast feedback:

# Validate keyword count (10-15 required)
def check_keywords(keywords_line: str) -> tuple[bool, int]:
    """Returns (is_valid, count)"""
    keywords = [k.strip() for k in keywords_line.split(',') if k.strip()]
    return (10 <= len(keywords) <= 15, len(keywords))

# Validate rule filename format
import re
def is_valid_filename(name: str) -> bool:
    """Must be NNN-lowercase-hyphenated"""
    return bool(re.match(r'^\d{3}-[a-z]+(-[a-z]+)*$', name))

# Validate TokenBudget format
def check_token_budget(value: str) -> bool:
    """Must be ~NUMBER format"""
    return bool(re.match(r'^~\d+$', value.strip()))

# Validate ContextTier
VALID_TIERS = {'Critical', 'High', 'Medium', 'Low'}
def check_context_tier(tier: str) -> bool:
    return tier.strip() in VALID_TIERS

Read the full file on GitHub · 111 lines

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. 9d ago First seen · 111 lines · 73 tokens per session scan A 4358770f5a18

Subscribe to this mod's changes

rule-creator is a skill published in the GitHub repository sfc-gh-myoung/ai_coding_rules (7 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 73 tokens to every session and 882 once invoked, about $0.0004 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 2026-08-31.

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