skill-creator

skill-creator is a skill for Claude Code, Codex from letitbk/claude-academic-setup. It costs 46 tokens per session (1,259 once invoked), scanned A, original, MIT.

A guide for creating and checking skills for AI coding agents using test-driven development, or TDD. TDD means writing tests first, checking that they fail, then writing instructions that make them pass.

In plain words
What is it for?
Use it to scaffold a skill, write pressure-test scenarios, validate its file structure, package it, and prepare it for distribution.
Why use it?
It helps verify that a skill changes agent behavior in the intended situations instead of merely looking well written.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: reads .claude/ paths; mentions subagents.

Good fit Use it to scaffold a skill, write pressure-test scenarios, validate its file structure, package it, and prepare it for distribution.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/letitbk/claude-academic-setup/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 letitbk/claude-academic-setup --skill skill-creator
Clone the repo
git clone --depth 1 https://github.com/letitbk/claude-academic-setup

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/letitbk/claude-academic-setup/skill-creator.svg)](https://agentmods.dev/skills/letitbk/claude-academic-setup/skill-creator)
Your own site
<a href="https://agentmods.dev/skills/letitbk/claude-academic-setup/skill-creator"><img src="https://agentmods.dev/badge/skills/letitbk/claude-academic-setup/skill-creator.svg" alt="Measured on agentmods" height="20"></a>
Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,259 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 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 5.1 $0.00046 $0.01259
Opus 5 $0.00023 $0.00629
Sonnet 5 $0.00009 $0.00252
Haiku 4.5 $0.00005 $0.00126

Measured 8d ago against content hash a7270317f121, 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 8d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/init_skill.py, scripts/package_skill.py, scripts/quick_validate.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/skill-creator/SKILL.md · 206 lines

How it starts

The opening of the file, as written. The whole thing — 206 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Creator

Create effective skills using TDD methodology with scaffolding scripts.

Overview

Skills are TDD applied to process documentation. Write test cases (pressure scenarios), watch them fail (baseline behavior), write the skill, watch tests pass, and refactor.

Core principle: If you didn't watch an agent fail without the skill, you don't know if the skill teaches the right thing.

Quick Start

# Initialize new skill
scripts/init_skill.py my-skill --path ~/.claude/skills

# Validate skill structure
scripts/quick_validate.py ~/.claude/skills/my-skill

# Package for distribution
scripts/package_skill.py ~/.claude/skills/my-skill

Skill Structure

skill-name/
├── SKILL.md              # Main reference (required)
├── scripts/              # Executable code (optional)
├── references/           # Documentation loaded as needed (optional)
└── assets/               # Templates, images, fonts (optional)

SKILL.md Frontmatter

Only name and description fields. Max 1024 chars total.

---
name: hyphen-case-name
description: Use when [specific triggering conditions]. Start with "Use when..."
---

CRITICAL: Description = when to use, NOT what skill does. Testing revealed that workflow summaries in descriptions cause agents to skip reading the full skill.

# ❌ BAD: Summarizes workflow
description: Use when executing plans - dispatches subagent with code review between tasks

# ✅ GOOD: Just triggers
description: Use when executing implementation plans with independent tasks

SKILL.md Body Structure

# Skill Name

## Overview
Core principle in 1-2 sentences.

## When to Use
Symptoms and use cases (bullets). When NOT to use.

## Core Pattern
Before/after or key workflow.

## Quick Reference
Table or bullets for scanning.

## Common Mistakes
What goes wrong + fixes.

Creation Process (TDD)

1. Understand with Examples

Ask: "What functionality should this skill support?" "Can you give usage examples?"

Read the full file on GitHub · 206 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 8d ago First seen · 206 lines · 46 tokens per session scan A a7270317f121

Subscribe to this mod's changes

skill-creator is a skill published in the GitHub repository letitbk/claude-academic-setup (43 stars, last pushed 2mo ago), licensed MIT. It adds 46 tokens to every session and 1,259 once invoked, about $0.0002 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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