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 filecompatibility: Environment requirementsmetadata: Additional key-value pairsallowed-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 invokereferences/: Supplementary documentationassets/: 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/