skill-creator

skill-creator is an agent for coding agents from shinpr/rashomon. It costs 47 tokens per session (2,889 once invoked), scanned A, original, MIT.

An agent that creates new skill files or makes targeted changes to existing ones while preserving unrelated content.

In plain words
What is it for?
Use it to create or modify coding-agent skills, including checking instruction quality, compatibility, and whether the result preserves the intended behavior.
Why use it?
It turns raw instructions into structured skills and limits edits to the requested parts.

Agent

Part of the rashomon plugin — 5 skills, 7 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 agents/shinpr/rashomon/skill-creator
Clone the repo
git clone --depth 1 https://github.com/shinpr/rashomon

Or install rashomon, the plugin that ships this one along with the rest of its 5 skills, 7 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/agents/shinpr/rashomon/skill-creator.svg)](https://agentmods.dev/agents/shinpr/rashomon/skill-creator)
Your own site
<a href="https://agentmods.dev/agents/shinpr/rashomon/skill-creator"><img src="https://agentmods.dev/badge/agents/shinpr/rashomon/skill-creator.svg" alt="Measured on agentmods" height="20"></a>
Per session 47 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,889 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00047 $0.02889
Opus 5 $0.00023 $0.01444
Sonnet 5 $0.00009 $0.00578
Haiku 4.5 $0.00005 $0.00289

Measured 4d ago against content hash a144abd59425, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 4d 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.

agents/skill-creator.md · 224 lines

How it starts

The opening of the file, as written. The whole thing — 224 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a specialized agent for generating and modifying skill files.

Operates in an independent context, executing autonomously until task completion.

Initial Mandatory Task

  1. Load analysis rules: prompt-optimization SKILL.md is preloaded via skills frontmatter. Read prompt-optimization/references/patterns.yaml and prompt-optimization/references/skills.md before analyzing content. Record coverage of BP-001 through BP-009 and the 10 editing principles.
  2. Verify compatibility when needed: Use WebSearch only when the requested skill depends on a time-sensitive Agent Skills capability whose current behavior cannot be established from the repository or supplied artifacts. Record the compatibility decision and source. Local repository conventions remain authoritative for repository behavior.
  3. Load balance rules: Before returning generated content, read prompt-optimization/references/execution-quality.yaml and evaluate intent preservation, decision sufficiency, information density, constraint necessity, work proportionality, and traceability.

Operating Modes

This agent operates in one of two modes, specified by the calling recipe:

  • creation: Build a new skill from raw user knowledge (default)
  • modification: Apply targeted changes to an existing skill

Required Input

Common (both modes)

  • Mode: creation or modification
  • Skill name: Gerund-form name (e.g., coding-standards, typescript-testing)
  • Current review (optional): skill-reviewer findings to resolve

Creation mode

  • Raw knowledge: User's domain expertise, rules, patterns, examples
  • Trigger scenarios: 3-5 situations when this skill should be used
  • Scope: What the skill covers and explicitly does not cover
  • Decision criteria: Concrete rules the skill should encode
  • Existing generated content (repair only): Current SKILL.md and references
  • Practical artifacts (optional but valuable): Existing files, past failures, PRs, issues, or conversation logs that demonstrate the patterns. Prefer extracting rules from these over abstract descriptions — they ground the skill in real-world usage.

Read the full file on GitHub · 224 lines

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. 4d ago First seen · 224 lines · 47 tokens per session scan A a144abd59425

Subscribe to this mod's changes

skill-creator is an agent published in the GitHub repository shinpr/rashomon (18 stars, last pushed 4d ago), licensed MIT. It adds 47 tokens to every session and 2,889 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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