Agent skill

Gm Skills

by Sstobo in Sstobo/Claude-Code-Game-Master

Skill-check resolution — when to roll, the DC ladder, fail-forward philosophy, and margin-based consequences.

Custom licenceAuto-check passed

Install Gm Skills

skills CLI
$ npx skills add Sstobo/Claude-Code-Game-Master --skill gm-skills -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install Sstobo/Claude-Code-Game-Master gm-skills --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/Sstobo/Claude-Code-Game-Master.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/gm-skills .claude/skills/gm-skills && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
gm-skills
GitHub stars
155
Token cost
~1.2k tokens
SKILL.md length
664 words
Files
1
Skills in repo
8
Repo updated
First seen
Licence
Custom licence

At a glance

Skill-check resolution — when to roll, the DC ladder, fail-forward philosophy, and margin-based consequences.

  • SKILL.md covers When to roll (dice add fun), Process, DC ladder and Narrate by margin, plus 4 more sections
  • Calls bash and uv

What it does

Gm Skills is an agent skill from Sstobo/Claude-Code-Game-Master. Skill-check resolution — when to roll, the DC ladder, fail-forward philosophy, and margin-based consequences. Load whenever the player attempts something uncertain ("I try to..."). Resolution runs through the generic core (d20 vs DC); this is the judgment framework for when/how.

Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

The repository describes itself as: Total conversion for Claude Code. Use RAG and the RPG ruleset apis to play a persistent adventure in any book or world of your choosing.

Example prompts

  • “I try to...”
  • “/gm-skills”

Requirements

  • Python 3

What it can do on your machine

Read from SKILL.md and the folder at commit dea9931. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • bash
    • uv

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md. Its commands use uv, which can reach the network depending on how they are called.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Gm Skills loads about 1.2k tokens when it runs. Until then it costs about 72 tokens; SKILL.md has 664 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~72
When it runs · the whole SKILL.md, loaded when a task matches
~1.2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 664 words (~1,213 tokens).

“The DC ladder below is 5e — use it only when the scene-context KIT block says dnd5e.”

— opening of SKILL.md by Sstobo, Custom licence
name
gm-skills

Read the full SKILL.md on GitHub

Files

Just SKILL.md in .claude/skills/gm-skills of Sstobo/Claude-Code-Game-Master.

Open the folder on GitHubat commit dea9931

Compare with similar skills

Gm Skills next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Gm Skills compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Gm Skills this skillSstobo/Claude-Code-Game-Master155—~1.2kAutomated safety check: PassCustom licence
Review Hog Resolution CriteriaPostHog/posthog40k—~1.4kAutomated safety check: PassCustom licence
Debug Failed Runactivepieces/activepieces25k—~3.7kAutomated safety check: WarnCustom licence
Review Hog Resolution Criteria GapsPostHog/posthog40k—~2kAutomated safety check: PassCustom licence
Review Hog Resolution Criteria SmallPostHog/posthog40k—~2kAutomated safety check: PassCustom licence
Gmail Message Forwardergoogleworkspace/cli31k—~763Automated safety check: PassApache-2.0

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More from Sstobo/Claude-Code-Game-Master

All 8 skills in this repo
  • Gm Social

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  • Gm Combat

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  • Gm Dungeon

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  • Gm Craft

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  • Gm Levelup

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    D&D-kit leveling — XP thresholds, the level-up ceremony, hit dice by class, and ASI/feat/subclass handling.

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  • Gm Spellcasting

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Questions about Gm Skills

What does Gm Skills do?

Skill-check resolution — when to roll, the DC ladder, fail-forward philosophy, and margin-based consequences. Gm Skills is an agent skill from Sstobo/Claude-Code-Game-Master. Skill-check resolution — when to roll, the DC ladder, fail-forward philosophy, and margin-based consequences.

How do I install Gm Skills in Claude Code?

Run `npx skills add Sstobo/Claude-Code-Game-Master --skill gm-skills -a claude-code`. Or copy the skill folder (.claude/skills/gm-skills in Sstobo/Claude-Code-Game-Master) into .claude/skills/gm-skills in your project. Claude Code loads it when a task matches its description.

How do I install Gm Skills in Codex?

Run `npx skills add Sstobo/Claude-Code-Game-Master --skill gm-skills -a codex`. Or copy the skill folder (.claude/skills/gm-skills in Sstobo/Claude-Code-Game-Master) into .agents/skills/gm-skills in your project. Codex loads it when a task matches its description.

Can I use Gm Skills in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add Sstobo/Claude-Code-Game-Master --skill gm-skills -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/gm-skills, .gemini/skills/gm-skills, .github/skills/gm-skills and .opencode/skills/gm-skills in your project.

What does Gm Skills need to run?

Going by SKILL.md and its folder, Gm Skills needs the command-line tools its instructions call (bash and uv). Our summary lists: Python 3.

Does Gm Skills access the network?

SKILL.md contains no URLs. Its commands use uv, which can reach the network depending on how they are called. This is read from the text; nothing was executed.

Is Gm Skills safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Gm Skills use?

Gm Skills has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.

How many tokens does Gm Skills use?

About 1.2k tokens (SKILL.md is roughly 4.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Gm Skills?

Skills that share tags, products or a category with Gm Skills: Review Hog Resolution Criteria (PostHog/posthog, 40k stars), Debug Failed Run (activepieces/activepieces, 25k stars), Review Hog Resolution Criteria Gaps (PostHog/posthog, 40k stars) and Review Hog Resolution Criteria Small (PostHog/posthog, 40k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Gm Skills?

Sstobo (a GitHub user) maintains it in Sstobo/Claude-Code-Game-Master, which has 155 GitHub stars. The repository holds 8 skills in this directory. The repository was last updated on August 16, 2026.

Source: Sstobo/Claude-Code-Game-Master on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.