create-rule

A workflow for creating a persistent Cursor rule file that gives an AI coding assistant ongoing project guidance. It can place the rule in the main repository or a named submodule and links it into Cursor's rules directory.

In plain words
What is it for?
Use it to create repository or submodule rules, choose their location, and set up the required Cursor symlink.
Why use it?
It prevents important instructions from being repeated in every conversation and keeps them available to Cursor automatically.

Skill for Claude CodeCodexCursor

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/markmhendrickson/foundation/create-rule
Any agent
npx skills add markmhendrickson/foundation --skill create-rule
Clone the repo
git clone --depth 1 https://github.com/markmhendrickson/foundation

Made for: Claude Code, Codex, Cursor.

Per session 11 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,793 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 94% 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 $0.00011 $0.01793
Opus 5 $0.00005 $0.00897
Sonnet 5 $0.00002 $0.00359
Haiku 4.5 $0.00001 $0.00179

Measured yesterday against content hash 379b39cdb91c, 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

94% identical to create-rule — 21 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.

.cursor/skills/create-rule/SKILL.md · 293 lines

How it starts

The opening of the file, as written. The whole thing — 293 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Create Rule

Create a new rule file with _rules suffix and automatically create symlink in .cursor/rules/.

SUBMODULE MODE: If a submodule name is provided (e.g., /create-rule foundation), create the rule in that submodule. If no submodule name is provided, create in the main repository's docs/ directory.

Command

create-rule [submodule_name]

Inputs

  • submodule_name (optional string): Submodule name to create rule in (e.g., "foundation"). If omitted, creates rule in main repository's docs/ directory.

Workflow Overview

If submodule name provided:

  1. Verify submodule exists
  2. Determine submodule rule location
  3. Prompt user for rule details
  4. Create rule file in submodule
  5. Run setup script to create symlink (if applicable)
  6. Exit after submodule rule creation

If no submodule name provided (default - repo mode):

  1. Prompt user for rule details
  2. Create rule file in docs/{location}/{name}_rules.md
  3. Include standard Agent Instructions template
  4. Run setup script to create symlink
  5. Verify symlink created

Tasks

Step 1: Determine Scope

If submodule name provided:

  1. Verify submodule exists:

    if ! git submodule status <submodule_name> >/dev/null 2>&1; then
      echo "❌ Submodule not found: <submodule_name>"
      exit 1
    fi
    
  2. Determine submodule rule location:

    • For foundation submodule: foundation/agent_instructions/cursor_rules/
    • For other submodules: Check for standard rule directories or prompt user
  3. Set context for submodule rule creation

If no submodule name provided:

  • Set context for main repository rule creation in docs/ directory

Step 2: Prompt User for Rule Details

Repository mode prompts:

  1. Rule file name (without _rules.md suffix)

    • Example: "entity_resolution" will become "entity_resolution_rules.md"
    • Validate: alphanumeric with underscores only
  2. Location in docs/ directory

    • Options: conventions, foundation, subsystems, architecture, developer, etc.
    • Validate: directory must exist or ask to create

Read the full file on GitHub · 293 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 · 293 lines · 11 tokens per session scan A 379b39cdb91c

Subscribe to this mod's changes

create-rule is a skill published in the GitHub repository markmhendrickson/foundation (2 stars, last pushed 1mo ago), licensed MIT. It adds 11 tokens to every session and 1,793 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to create-rule, differing in 21 lines, and is treated as a copy.

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