/skill-writer

name: skill-writer
description: Guide users through creating Agent Skills for Claude Code. Use when the user wants to create, write, author, or design a new Skill, or needs help with SKILL.md files, frontmatter, or skill structure.

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!`

• **description**:
• Max 1024 characters
• Include BOTH what it does AND when to use it
• Use specific trigger words users would say
• Mention file types, operations, and context

**Optional frontmatter fields**:

• **allowed-tools**: Restrict tool access (comma-separated list)

  allowed-tools: Read, Grep, Glob

Use for:

• Read-only Skills
• Security-sensitive workflows
• Limited-scope operations

Step 5: Write effective descriptions

The description is critical for Claude to discover your Skill.

**Formula**: `[What it does] + [When to use it] + [Key triggers]`

**Examples**:

✅ **Good**:

description: Extract text and tables from PDF files, fill forms, merge documents. Use when working with PDF files or when the user mentions PDFs, forms, or document extraction.

✅ **Good**:

description: Analyze Excel spreadsheets, create pivot tables, and generate charts. Use when working with Excel files, spreadsheets, or analyzing tabular data in .xlsx format.

❌ **Too vague**:

description: Helps with documents
description: For data analysis

**Tips**:

• Include specific file extensions (.pdf, .xlsx, .json)
• Mention common user phrases ("analyze", "extract", "generate")
• List concrete operations (not generic verbs)
• Add context clues ("Use when...", "For...")

Step 6: Structure the Skill content

Use clear Markdown sections:

# Skill Name

Brief overview of what this Skill does.

## Quick start

Provide a simple example to get started immediately.

## Instructions

Step-by-step guidance for Claude:
1. First step with clear action
2. Second step with expected outcome
3. Handle edge cases

## Examples

Show concrete usage examples with code or commands.

## Best practices

- Key conventions to follow
- Common pitfalls to avoid
- When to use vs. not use

## Requirements

List any dependencies or prerequisites:
```bash
pip install package-name

Advanced usage

For complex scenarios, see [reference.md](reference.md).

### Step 7: Add supporting files (optional)

Create additional files for progressive disclosure:

**reference.md**: Detailed API docs, advanced options
**examples.md**: Extended examples and use cases
**scripts/**: Helper scripts and utilities
**templates/**: File templates or boilerplate

Reference them from SKILL.md:
```markdown
For advanced usage, see [reference.md](reference.md).

Run the helper script:
\`\`\`bash
python scripts/helper.py input.txt
\`\`\`

Step 8: Validate the Skill

Check these requirements:

✅ **File structure**:

• [ ] SKILL.md exists in correct location
• [ ] Directory name matches frontmatter `name`

✅ **YAML frontmatter**:

• [ ] Opening `---` on line 1
• [ ] Closing `---` before content
• [ ] Valid YAML (no tabs, correct indentation)
• [ ] `name` follows naming rules
• [ ] `description` is specific and < 1024 chars

✅ **Content quality**:

• [ ] Clear instructions for Claude
• [ ] Concrete examples provided
• [ ] Edge cases handled
• [ ] Dependencies listed (if any)

✅ **Testing**:

• [ ] Description matches user questions
• [ ] Skill activates on relevant queries
• [ ] Instructions are clear and actionable

Step 9: Test the Skill

1. **Restart Claude Code** (if running) to load the Skill

2. **Ask relevant questions** that match the description:

   Can you help me extract text from this PDF?

3. **Verify activation**: Claude should use the Skill automatically

4. **Check behavior**: Confirm Claude follows the instructions correctly

Step 10: Debug if needed

If Claude doesn't use the Skill:

1. **Make description more specific**:

• Add trigger words
• Include file types
• Mention common user phrases

2.