Skill Creator

This skill helps you create new Agent Skills that follow the official specification.

When to Use

• User wants to create a new skill
• User needs to scaffold a skill directory structure
• User asks about skill format or structure
• User wants to evaluate or validate an existing skill (e.g., "〜のスキルを評価して")

Steps to Create a New Skill

1. Gather Requirements

Ask the user for:

• Skill name: Must be lowercase, use hyphens, 1-64 characters (e.g., pdf-processing, code-review)
• Description: What the skill does and when to use it (1-1024 characters)
• Optional: License, compatibility requirements, metadata

2. Confirm Installation Location

IMPORTANT: Before creating any files, confirm the installation location with the user.

Default Installation Path: .claude/skills

The installation path varies by tool/environment. Determine a reasonable default based on:

• Current working directory structure
• Existing skills directories (e.g., ./skills/, ./.claude/skills/)
• Project conventions

Then ask the user for confirmation:

スキル「{skill-name}」を以下の場所に作成します：
  {full-path}/{skill-name}/

この場所でよろしいですか？別の場所を指定することもできます。

Only proceed after user confirms the location.

3. Create Directory Structure

Create the skill directory at the confirmed location:

skill-name/
├── SKILL.md          # Required - main skill file
├── references/       # Optional - additional documentation
├── scripts/          # Optional - executable code
└── assets/           # Optional - static resources

4. Create SKILL.md

The SKILL.md file must contain:

1. YAML Frontmatter (required):

   ---
   name: skill-name
   description: A clear description of what this skill does and when to use it.
   ---
   

2. Markdown Body (recommended sections):

   • Step-by-step instructions
   • Examples of inputs and outputs
   • Common edge cases

5. Validation Checklist

Before finishing, verify:

• name field matches the directory name
• name is lowercase with hyphens only, no consecutive hyphens
• description clearly explains what the skill does AND when to use it
• Main SKILL.md is under 500 lines
• File references use relative paths from skill root

Name Constraints

The name field must:

• Be 1-64 characters
• Use only lowercase letters, numbers, and hyphens (a-z, 0-9, -)
• Not start or end with -
• Not contain consecutive hyphens (--)
• Match the parent directory name exactly

Valid: pdf-processing, code-review, data-analysis Invalid: PDF-Processing, -pdf, pdf--processing, pdf-

Example SKILL.md

---
name: example-skill
description: Does X and Y. Use when the user mentions A, B, or C.
license: MIT
metadata:
  author: your-name
  version: "1.0"
---

# Example Skill

Instructions for the agent go here.

## Usage

1. First step
2. Second step

## Examples

Input: ...
Output: ...

Optional Directories

references/

Additional documentation loaded on demand. Keep files focused and small.

scripts/

Executable code (Python, Bash, JavaScript). Should be self-contained with clear error messages.

assets/

Static resources: templates, images, data files, schemas.

Evaluating an Existing Skill

When the user asks to evaluate a skill (e.g., "〜のスキルを評価して"), follow these steps:

1. Read the Specification

First, read skills-spec.md to understand the complete format requirements.

2. Read the Target Skill

Read the target skill's SKILL.md file and any related files.

3. Check Against Specification

Evaluate the skill against these criteria:

Required Checks:

• SKILL.md exists in the skill directory
• YAML frontmatter is present and valid
• name field exists and follows naming rules:
  • 1-64 characters
  • Lowercase letters, numbers, hyphens only
  • No leading/trailing hyphens
  • No consecutive hyphens (--)
  • Matches parent directory name
• description field exists (1-1024 characters)
• Description explains both WHAT the skill does AND WHEN to use it

Recommended Checks:

• SKILL.md is under 500 lines
• Body contains step-by-step instructions
• Examples are provided
• File references use relative paths
• Reference files are focused and not too large

Optional Field Checks (if present):

• license field is concise
• compatibility field is under 500 characters
• metadata has string keys and string values
• allowed-tools is space-delimited

4. Report Findings

Present the evaluation results to the user:

1. List all issues found (errors and warnings)
2. Provide specific suggestions for each issue
3. Show example corrections where applicable

5. Wait for User Permission

IMPORTANT: Do NOT make any modifications automatically. Always:

1. Present the evaluation report
2. Ask the user if they want to apply the suggested fixes
3. Only proceed with modifications after explicit user approval

Example response format:

## 評価結果

### エラー (必須修正)
1. `name` フィールドが...

### 警告 (推奨修正)
1. `description` が...

### 修正案
[具体的な修正内容]

これらの修正を適用しますか？

Reference

For the complete specification, see skills-spec.md.