create-rule

A workflow for creating Cursor Rules: Markdown files that give an AI coding assistant lasting instructions about a project's standards and conventions.

In plain words
What is it for?
Use it to create or update rules in `.cursor/rules/`, define project conventions, or add file-specific guidance using patterns such as `backend/**/*.py`.
Why use it?
It turns informal coding expectations into written guidance that the assistant can reuse, while clarifying whether each rule applies everywhere or only to matching files.

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/xyruscode/ai-sync/create-rule
Any agent
npx skills add XyrusCode/ai-sync --skill create-rule
Clone the repo
git clone --depth 1 https://github.com/XyrusCode/ai-sync

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 845 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod 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 $0.00845
Opus 5 $0.00026 $0.00423
Sonnet 5 $0.00010 $0.00169
Haiku 4.5 $0.00005 $0.00085

Measured yesterday against content hash fe8499dfe93e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

create-rule 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 yesterday.

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.

Origin

This is a copy

100% identical to create-rule — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/create-rule/SKILL.md · 165 lines

How it starts

The opening of the file, as written. The whole thing — 165 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Creating Cursor Rules

Create project rules in .cursor/rules/ to provide persistent context for the AI agent.

Gather Requirements

Before creating a rule, determine:

  1. Purpose: What should this rule enforce or teach?
  2. Scope: Should it always apply, or only for specific files?
  3. File patterns: If file-specific, which glob patterns?

Inferring from Context

If you have previous conversation context, infer rules from what was discussed. You can create multiple rules if the conversation covers distinct topics or patterns. Don't ask redundant questions if the context already provides the answers.

Required Questions

If the user hasn't specified scope, ask:

  • "Should this rule always apply, or only when working with specific files?"

If they mentioned specific files and haven't provided concrete patterns, ask:

  • "Which file patterns should this rule apply to?" (e.g., **/*.ts, backend/**/*.py)

It's very important that we get clarity on the file patterns.

Use the AskQuestion tool when available to gather this efficiently.


Rule File Format

Rules are .mdc files in .cursor/rules/ with YAML frontmatter:

.cursor/rules/
  typescript-standards.mdc
  react-patterns.mdc
  api-conventions.mdc

File Structure

---
description: Brief description of what this rule does
globs: **/*.ts  # File pattern for file-specific rules
alwaysApply: false  # Set to true if rule should always apply
---

# Rule Title

Your rule content here...

Frontmatter Fields

Field Type Description
description string What the rule does (shown in rule picker)
globs string File pattern - rule applies when matching files are open
alwaysApply boolean If true, applies to every session

Rule Configurations

Always Apply

For universal standards that should apply to every conversation:

---
description: Core coding standards for the project
alwaysApply: true
---

Read the full file on GitHub · 165 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. yesterday First seen · 165 lines · 52 tokens per session scan A fe8499dfe93e

Subscribe to this mod's changes

create-rule is a skill published in the GitHub repository XyrusCode/ai-sync (2 stars, last pushed 2d ago), licensed MIT. It adds 52 tokens to every session and 845 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to create-rule, differing in 0 lines, and is treated as a copy.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

next-cache-components-adoption

Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…

vercel/next.js · 95 tokens

babysit-pr

Babysit a GitHub pull request after creation by continuously polling review comments, CI checks/workflow runs, and mergeability state until the PR is merged/closed or user help is required. Diagnose failures, retry likely flaky failures up to 3 times, auto-fix/push branch-related issues when appropriate, and keep…

openai/codex · 114 tokens

imagegen

Generate or edit raster images when the task benefits from AI-created bitmap visuals such as photos, illustrations, textures, sprites, mockups, or transparent-background cutouts. Use when Codex should create a brand-new image, transform an existing image, or derive visual variants from references, and the output…

openai/codex · 113 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens

next-cache-components-optimizer

Drive a Next.js route to instant navigation by setting up an agentic loop, under Cache Components / PPR, on initial load (hard navigation) and client-side navigation (soft navigation). Encode the goal as a failing @next/playwright instant() e2e and work it to green, one verified route at a time; the shipped test then…

vercel/next.js · 170 tokens