A framework for deciding and resolving uncertain actions in a tabletop role-playing game. It uses a twenty-sided die compared with a difficulty number and supports consequences based on how well the roll goes.

It is for resolving attempts such as trying to perform a risky or uncertain action.

It helps the game master decide when a roll is needed and what different results mean.

How Sstobo/Claude-Code-Game-Master configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to Sstobo/Claude-Code-Game-Master. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/Sstobo/Claude-Code-Game-Master/main/.claude/skills/gm-skills/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/Sstobo/Claude-Code-Game-Master

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/sstobo/claude-code-game-master/gm-skills/github.svg)](https://agentmods.dev/skills/sstobo/claude-code-game-master/gm-skills)

Your own site

<a href="https://agentmods.dev/skills/sstobo/claude-code-game-master/gm-skills"><img src="https://agentmods.dev/badge/skills/sstobo/claude-code-game-master/gm-skills/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/sstobo/claude-code-game-master/gm-skills"><img src="https://agentmods.dev/badge/skills/sstobo/claude-code-game-master/gm-skills.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,192 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 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.

Model	Per session	Once invoked
Fable 5.1	$0.00059	$0.01192
Opus 5.5	$0.00024	$0.00477
Sonnet 5.5	$0.00012	$0.00238
Haiku 4.5	$0.00006	$0.00119

Measured 2mo ago against content hash 36326726c304, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

gm-skills 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 2mo 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.

.claude/skills/gm-skills/SKILL.md · 55 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

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.

2mo ago First seen · 55 lines · 59 tokens per session scan A 36326726c304

Subscribe to this mod's changes

gm-skills is a skill published in the GitHub repository Sstobo/Claude-Code-Game-Master (161 stars, last pushed 2mo ago), with no licence file. It adds 59 tokens to every session and 1,192 once invoked, about $0.0002 per session on Opus 5.5. 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.

Game development claude rpg story

gm-skills next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
gm-skillsSstobo/Claude-Code-Game-Master	Skill	161	2mo ago	none	A	59	Claude Code
html-ppt-zhangzara-8-bit-orbitnexu-io/open-design	Skill	106k	yesterday	Apache-2.0	A	53	Claude Code, Codex
game-storytellingericrisco/rsc-harness	Skill	503	2d ago	MIT	A	82	Claude Code, Codex
rpgmaker-mv-mcpDiegoLopez0208/RpgMakerMVUltimate-MCP	Skill	30	25d ago	MIT	A	139	Claude Code, Codex
textproductionellmos-ai/skills	Skill	9	3d ago	MIT	A	84	Claude Code, Codex
flame-systemsmiles990/claude-software-skills	Skill	26	9mo ago	MIT	A	30	Claude Code
rpgellmos-ai/skills	Skill	9	3d ago	MIT	A	23	Claude Code, Codex

Claude-Code-Game-Master: Skill for Claude Code