skill-creator

skill-creator is a skill for Claude Code, Codex from cynthiajones34/GBrain. It costs 50 tokens per session (573 once invoked), scanned A, a copy of skill-creator, MIT.

A tool for creating new agent skills, which are reusable instructions for handling particular tasks.

In plain words
What is it for?
Use it to define a skill’s instructions, triggers, outputs, and limits, then update the skill registry and run conformance tests.
Why use it?
It helps keep new skills consistent, prevents overlap with existing skills, and checks that required project files are updated.

Skill for Claude CodeCodex

Which agent this was written for is unclear — built for gbrain. Also seen: built for gbrain.

Good fit Use it to define a skill’s instructions, triggers, outputs, and limits, then update the skill registry and run conformance tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cynthiajones34/gbrain/skill-creator
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.

Any agent
npx skills add cynthiajones34/GBrain --skill skill-creator
Clone the repo
git clone --depth 1 https://github.com/cynthiajones34/GBrain

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 skill-creator

README.md
[![agentmods](https://agentmods.dev/badge/skills/cynthiajones34/gbrain/skill-creator.svg)](https://agentmods.dev/skills/cynthiajones34/gbrain/skill-creator)
Your own site
<a href="https://agentmods.dev/skills/cynthiajones34/gbrain/skill-creator"><img src="https://agentmods.dev/badge/skills/cynthiajones34/gbrain/skill-creator.svg" alt="Measured on agentmods" height="20"></a>
Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 573 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 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 5.1 $0.00050 $0.00573
Opus 5 $0.00025 $0.00287
Sonnet 5 $0.00010 $0.00115
Haiku 4.5 $0.00005 $0.00057

Measured 7d ago against content hash 4a11f8935d42, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

skill-creator 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 7d 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.

Origin

This is a copy

100% identical to skill-creator — 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/skill-creator/SKILL.md · 83 lines

What it actually says

Skill Creator

Contract

This skill guarantees:

  • New skill follows conformance standard (frontmatter + required sections)
  • MECE check: no overlap with existing skills' triggers
  • Manifest.json updated
  • RESOLVER.md updated with routing entry
  • Skill passes conformance tests (bun test test/skills-conformance.test.ts)

Phases

  1. Identify the gap. What capability is missing? What user intent has no skill?
  2. MECE check. Review skills/manifest.json and skills/RESOLVER.md. Does any existing skill already cover this? If so, extend it instead of creating a new one.
  3. Create SKILL.md. Use this template:
---
name: {skill-name}
version: 1.0.0
description: |
  {One paragraph describing what the skill does and when to use it.}
triggers:
  - "{trigger phrase 1}"
  - "{trigger phrase 2}"
tools:
  - {tool1}
  - {tool2}
mutating: {true|false}
---

# {Skill Title}

## Contract
{What this skill guarantees — 3-5 bullet points}

## Phases
{Numbered workflow steps}

## Output Format
{What good output looks like}

## Anti-Patterns
{What NOT to do — 3-5 items}

## Tools Used
{GBrain operations used, with descriptions}
  1. Add to manifest. Update skills/manifest.json with name, path, description.
  2. Add to resolver. Update skills/RESOLVER.md with routing entry in the appropriate category.
  3. Verify. Run bun test test/skills-conformance.test.ts to confirm the new skill passes.

Output Format

New skills/{name}/SKILL.md file + updated manifest + updated resolver.

Anti-Patterns

  • Creating a skill that overlaps with an existing one (violates MECE)
  • Skipping the MECE check against existing skills
  • Creating a skill without triggers in frontmatter
  • Not updating manifest.json and RESOLVER.md
  • Creating a skill without an Anti-Patterns section
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. 7d ago First seen · 83 lines · 50 tokens per session scan A 4a11f8935d42

Subscribe to this mod's changes

skill-creator is a skill published in the GitHub repository cynthiajones34/GBrain (0 stars, last pushed 1mo ago), licensed MIT. It adds 50 tokens to every session and 573 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 skill-creator, differing in 0 lines, and is treated as a copy.