Rule forge

Rule forge is a skill for Claude Code, Codex from 1A7432/loreweaver. It costs 61 tokens per session (536 once invoked), scanned A, original, MIT.

A tool for creating and installing a new tabletop role-playing game rule system from a natural-language description. A tabletop role-playing game is a shared story game in which rules resolve what characters can do.

In plain words
What is it for?
Use it to define attributes, skills, dice or check methods, derived statistics, and starting values for a new game system.
Why use it?
It lets the game facilitator add a custom ruleset when the available systems do not fit the planned game.

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/1a7432/loreweaver/rule-forge
Any agent
npx skills add 1A7432/loreweaver --skill rule-forge
Clone the repo
git clone --depth 1 https://github.com/1A7432/loreweaver

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 forge

README.md
[![agentmods](https://agentmods.dev/badge/skills/1a7432/loreweaver/rule-forge.svg)](https://agentmods.dev/skills/1a7432/loreweaver/rule-forge)
Your own site
<a href="https://agentmods.dev/skills/1a7432/loreweaver/rule-forge"><img src="https://agentmods.dev/badge/skills/1a7432/loreweaver/rule-forge.svg" alt="Measured on agentmods" height="20"></a>
Per session 61 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 536 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00061 $0.00536
Opus 5 $0.00030 $0.00268
Sonnet 5 $0.00012 $0.00107
Haiku 4.5 $0.00006 $0.00054

Measured 4d ago against content hash 7543e5504cb6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Rule forge 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 4d 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-forge/SKILL.md · 43 lines

What it actually says

Rule forge

You can author an entirely new TTRPG rule system, not just play the ones already installed (coc7, dnd5e). When the keeper describes a rule system they want available -- its core attributes/skills, how a check succeeds or fails, and any derived stats it needs -- call generate_rulepack with a clear, self-contained description of it. Only call it when the keeper is explicitly asking for a new rule system to be authored; never speculatively, and never in response to ordinary play.

CoC 7e and D&D 5e are the reference packs: both are just rulepacks/<id>.yaml data files, so a good description gives the same kind of detail their own sheets have.

A good description to pass along:

  • names the system plainly (genre, tone, or the real TTRPG it's modeling, if any)
  • lists its core attributes/skills and roughly what a starting character's values look like
  • says how a check is resolved (roll-under, roll-over a target, dice-pool successes, ...)
  • names any derived stats it needs (health, a damage bonus, per-attribute modifiers, ...) and, if you know it, roughly how each should be computed

What makes a good rule system: internally consistent math, sensible starting defaults for every stat, and derived stats expressed as data wherever possible rather than reaching for a named code computer. generate_rulepack will refuse (writing nothing) if the generated pack doesn't parse, if its derived stats don't compile through the safe formula vocabulary, or if its id would collide with a built-in system.

After generate_rulepack responds, tell the keeper plainly what was created (or why it wasn't, if it failed) and note that the new system is now discoverable by its id/names.

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. 4d ago First seen · 43 lines · 61 tokens per session scan A 7543e5504cb6

Subscribe to this mod's changes

Rule forge is a skill published in the GitHub repository 1A7432/loreweaver (49 stars, last pushed 3d ago), licensed MIT. It adds 61 tokens to every session and 536 once invoked, about $0.0003 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 2026-08-30.

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