skill-creator

Skill Creator

This skill guides the creation of new Agent Skills that conform to the Agent Skills specification. Follow these instructions whenever you need to create a new skill for any capability.

When to Use This Skill

• User asks to create a new skill
• User requests adding a skill for a specific capability
• User wants to define or build a skill
• User needs to package knowledge or workflows as a reusable skill

Agent Skills Core Concepts

Skills are portable, self-documenting packages that extend AI agent capabilities. Each skill is a directory containing a SKILL.md file with instructions.

For complete specification details, see references/spec.md.

Progressive Disclosure Architecture

Skills use a three-tier loading strategy for efficient context management:

Tier	What is Loaded	When	Token Cost
Catalog	name + description	Session start	~50-100 tokens
Instructions	Full SKILL.md body	Skill activated	<5000 tokens recommended
Resources	Scripts, references, assets	When referenced	Varies

Creating a New Skill

Follow these six steps to create a skill:

Step 1: Determine Skill Purpose

Before creating files, clearly define:

• What capability does this skill provide?
• When should an agent use this skill?
• What keywords would trigger this skill?

Step 2: Create Directory Structure

skill-name/
├── SKILL.md          # Required
├── scripts/          # Optional: executable code
├── references/       # Optional: documentation
└── assets/           # Optional: templates, resources

The directory name must match the skill name.

Step 3: Write Frontmatter

The SKILL.md file must start with YAML frontmatter containing required fields.

Required fields:

• name: Skill identifier (1-64 characters, lowercase letters and hyphens only)
• description: What the skill does AND when to use it (1-1024 characters)

Optional fields:

• license: License name or file
• compatibility: Environment requirements
• metadata: Additional key-value pairs
• allowed-tools: Pre-approved tools (experimental)

For detailed field specifications, see references/frontmatter.md.

Step 4: Write Instruction Content

The Markdown body after frontmatter contains skill instructions. There are no format restrictions, but include:

• When to use this skill
• Step-by-step instructions
• Examples of inputs and outputs
• Common edge cases

For writing guidelines, see references/content.md.

Step 5: Add Optional Resources

If your skill requires scripts, references, or assets, add them to the appropriate subdirectories:

• scripts/: Executable code that the skill instructions may invoke
• references/: Supplementary documentation
• assets/: Templates, data files, or other resources

For script support details, see references/scripts/overview.md.

Step 6: Validate

Verify your skill follows the specification:

npx skills-ref validate ./skill-name

For validation details, see references/spec.md.

Quick Reference

Valid Name Patterns

Valid:   pdf-processing, data-analysis, code-review
Invalid: PDF-Processing (uppercase), -pdf (starts with hyphen), pdf--processing (consecutive hyphens)

Good Description Example

description: Extracts text and tables from PDF files, fills PDF forms, and merges multiple PDFs. Use when working with PDF documents or when the user mentions PDFs, forms, or document extraction.

Additional Resources

• Specification: references/spec.md
• Frontmatter fields: references/frontmatter.md
• Content writing: references/content.md
• Script support overview: references/scripts/overview.md
• Tool runners: references/scripts/tool-runner.md
• Python scripts: references/scripts/python.md
• Deno scripts: references/scripts/deno.md
• Bun scripts: references/scripts/bun.md
• Examples: references/examples/