skill-creator

skill-creator is a skill for Claude Code, Codex from jdforsythe/forge. It costs 147 tokens per session (3,470 once invoked), scanned B, original, MIT.

A skill-building tool for creating Claude Code and Cowork skills, which are reusable instruction sets for AI assistants. It uses research-based guidance for wording, structure, triggering, and quality checks.

In plain words
What is it for?
Use it to design, structure, and review reusable assistant skills, including their trigger wording, reference materials, examples, and evaluation rules.
Why use it?
It helps turn a task into instructions that an AI assistant can identify and follow consistently. It also checks for common instruction-design problems and unnecessary jargon.

Skill for Claude CodeCodex

Part of the forge plugin — 4 skills, 3 agents shipped together

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

Made for: Claude Code, Codex.

Or install forge, the plugin that ships this one along with the rest of its 4 skills, 3 agents.

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/jdforsythe/forge/skill-creator.svg)](https://agentmods.dev/skills/jdforsythe/forge/skill-creator)
Your own site
<a href="https://agentmods.dev/skills/jdforsythe/forge/skill-creator"><img src="https://agentmods.dev/badge/skills/jdforsythe/forge/skill-creator.svg" alt="Measured on agentmods" height="20"></a>
Per session 147 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,470 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 $0.00147 $0.03470
Opus 5 $0.00073 $0.01735
Sonnet 5 $0.00029 $0.00694
Haiku 4.5 $0.00015 $0.00347

Measured 5d ago against content hash b1844bdf9d46, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

skill-creator scanned grade B with 1 finding 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 5d 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.

Asks the agent to reveal its instructionsmediumSystem prompt leakage

Directions to print, repeat or translate the system prompt extract configuration the operator did not intend to expose.

### 9. Reasoning-Echo Instructions
skills/skill-creator/SKILL.md · 255 lines

How it starts

The opening of the file, as written. The whole thing — 255 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Creator

Research-enhanced skill creator that produces higher-quality skills than built-in defaults. Every design decision is grounded in how transformers process context.


Expert Vocabulary Payload

Prompt Engineering & Routing: expert vocabulary payload, dual-register description, vocabulary routing, distributional convergence, attention budget, distribution center, right altitude, retrieval anchor

Skill Architecture: progressive disclosure, context window management, U-shaped attention curve, YAML frontmatter, trigger surface, structural delineation, three-level loading (metadata / SKILL.md / references)

Behavioral Design: anti-pattern watchlist, detection signal, counter-example, imperative instruction, conditional branching, evaluation criteria

Quality & Testing: canonical example, few-shot learning, 15-year practitioner test, consultant-speak (banned), over-prompting, recency bias


Anti-Pattern Watchlist

These are anti-patterns in the skills this creator generates. Scan every generated SKILL.md against this list before delivery.

1. Generic Consultant-Speak in Vocabulary

Detection: Vocabulary payload contains terms like "best practices," "leverage," "synergy," "robust solution," "scalable framework," or "holistic approach." Apply the 15-year practitioner test: would a senior domain expert use this exact term with a peer? If not, it fails. Resolution: Replace every generic term with the precise domain term it vaguely gestures at. "Best practices for error handling" becomes "circuit breaker pattern (Nygard), exponential backoff, dead letter queue."

2. Over-Prompting

Detection: SKILL.md exceeds 500 lines. The same concept is stated 2-3 times in different words "for emphasis." Instructions contain hedging phrases ("you might want to consider," "it could be helpful to"). Resolution: State each instruction once, in imperative form. Remove hedging. Move heavy reference content to references/. Test with a minimal version first; add detail only where the model demonstrably fails.

Read the full file on GitHub · 255 lines

Files

What ships with it

2 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. 5d ago First seen · 255 lines · 147 tokens per session scan B b1844bdf9d46

Subscribe to this mod's changes

skill-creator is a skill published in the GitHub repository jdforsythe/forge (151 stars, last pushed 2mo ago), licensed MIT. It adds 147 tokens to every session and 3,470 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it B with 1 finding (asks the agent to reveal its instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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