skill-writer

skill-writer is a skill for Claude Code, Codex from virgoC0der/awesome-claude-code. It costs 48 tokens per session (2,240 once invoked), scanned B, a copy of skill-writer, MIT.

A guide for creating Agent Skills for Claude Code, including their SKILL.md files, settings, and folder structure.

In plain words
What is it for?
Use it to create, update, organize, or troubleshoot Claude Code Skills, including deciding their scope and where to store them.
Why use it?
It helps turn a repeated workflow or prompt into a Skill that Claude Code can discover and use correctly.

Skill for Claude CodeCodex

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

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is python scripts/helper.py input.txt.

Good fit Use it to create, update, organize, or troubleshoot Claude Code Skills, including deciding their scope and where to store them.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/virgoC0der/awesome-claude-code
agentmods
npx agentmods add skills/virgoc0der/awesome-claude-code/skill-writer

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-writer

README.md
[![agentmods](https://agentmods.dev/badge/skills/virgoc0der/awesome-claude-code/skill-writer.svg)](https://agentmods.dev/skills/virgoc0der/awesome-claude-code/skill-writer)
Your own site
<a href="https://agentmods.dev/skills/virgoc0der/awesome-claude-code/skill-writer"><img src="https://agentmods.dev/badge/skills/virgoc0der/awesome-claude-code/skill-writer.svg" alt="Measured on agentmods" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,240 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin 95% 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 $0.00048 $0.02240
Opus 5 $0.00024 $0.01120
Sonnet 5 $0.00010 $0.00448
Haiku 4.5 $0.00005 $0.00224

Measured 7d ago against content hash 18e812b5a871, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade B, and why

skill-writer 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 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.

Enumerates other installed skillsmediumAgent snooping

Other skills' SKILL.md files reveal prompts, capabilities and secrets that should be invisible to peers.

ls ~/.claude/skills/skill-name/SKILL.md
Origin

This is a copy

95% identical to skill-writer — 27 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-writer/SKILL.md · 386 lines

How it starts

The opening of the file, as written. The whole thing — 386 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Writer

This Skill helps you create well-structured Agent Skills for Claude Code that follow best practices and validation requirements.

When to use this Skill

Use this Skill when:

  • Creating a new Agent Skill
  • Writing or updating SKILL.md files
  • Designing skill structure and frontmatter
  • Troubleshooting skill discovery issues
  • Converting existing prompts or workflows into Skills

Instructions

Step 1: Determine Skill scope

First, understand what the Skill should do:

  1. Ask clarifying questions:

    • What specific capability should this Skill provide?
    • When should Claude use this Skill?
    • What tools or resources does it need?
    • Is this for personal use or team sharing?
  2. Keep it focused: One Skill = one capability

    • Good: "PDF form filling", "Excel data analysis"
    • Too broad: "Document processing", "Data tools"

Step 2: Choose Skill location

Determine where to create the Skill:

Personal Skills (~/.claude/skills/):

  • Individual workflows and preferences
  • Experimental Skills
  • Personal productivity tools

Project Skills (.claude/skills/):

  • Team workflows and conventions
  • Project-specific expertise
  • Shared utilities (committed to git)

Step 3: Create Skill structure

Create the directory and files:

# Personal
mkdir -p ~/.claude/skills/skill-name

# Project
mkdir -p .claude/skills/skill-name

For multi-file Skills:

skill-name/
├── SKILL.md (required)
├── reference.md (optional)
├── examples.md (optional)
├── scripts/
│   └── helper.py (optional)
└── templates/
    └── template.txt (optional)

Step 4: Write SKILL.md frontmatter

Create YAML frontmatter with required fields:

---
name: skill-name
description: Brief description of what this does and when to use it
---

Field requirements:

  • name:
    • Lowercase letters, numbers, hyphens only
    • Max 64 characters
    • Must match directory name
    • Good: pdf-processor, git-commit-helper
    • Bad: PDF_Processor, Git Commits!

Read the full file on GitHub · 386 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. 7d ago First seen · 386 lines · 48 tokens per session scan B 18e812b5a871

Subscribe to this mod's changes

skill-writer is a skill published in the GitHub repository virgoC0der/awesome-claude-code (1 stars, last pushed 9mo ago), licensed MIT. It adds 48 tokens to every session and 2,240 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 1 finding (enumerates other installed skills). It is 95% identical to skill-writer, differing in 27 lines, and is treated as a copy.

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