SKILL.md Format Specification

VerifiedSafe

Describes the SKILL.md format used by n-skills, following the agentskills.io standard. Specifies required and optional frontmatter, body structure, bundled resources, and best practices. Helps in creating or understanding standardized AI coding skills.

Sby Skills Guide Bot
DocumentationBeginner
606/2/2026
Claude CodeCodex
#skill-definition#markdown-format#agentskills#documentation-standards

Recommended for

Our review

This skill defines the structure for creating SKILL.md files that describe AI agent skills, including frontmatter, body sections, and bundled resources.

Strengths

  • Provides a standardized format for skill documentation.
  • Includes both required and optional frontmatter fields.
  • Allows bundling of additional resources like scripts and references.
  • Promotes best practices like front-loading triggers.

Limitations

  • Does not cover how to actually implement the skill logic.
  • Limited to text-based documentation, not executable code.
  • May not be compatible with all AI agent platforms without adaptation.
When to use it

When you need to create a reusable, well-documented skill definition for an AI agent following the agentskills.io standard.

When not to use it

When you are looking for a ready-made skill implementation rather than a documentation template.

Security analysis

Safe
Quality score90/100

This SKILL.md is purely a documentation specification with no executable code, network operations, or system modifications. It poses no security risk.

No concerns found

Examples

Create a code review skill definition
Create a SKILL.md file for a skill that reviews Python code for style and security issues. Include frontmatter with description, triggers like 'review this code', and a setup section requiring pylint and bandit.
Generate a SKILL.md template
Generate a SKILL.md template following the agentskills.io standard with required frontmatter (name, description), a setup section, and an examples section. Use 'example-skill' as the name.
Document a data analysis skill
Write a SKILL.md for a skill that analyzes CSV data and generates summary statistics. Include compatibility for claude-code and codex, and reference a scripts/analyze.py file.

SKILL.md Format Specification

This document describes the SKILL.md format used by n-skills, which follows the agentskills.io standard.

Required Frontmatter

---
name: skill-name           # lowercase, hyphens only
description: |             # Include trigger phrases
  What it does.
  When to use it.
  Requirements.
---

Optional Frontmatter

version: 1.0.0
license: Apache-2.0
author:
  name: Your Name
  github: username
keywords: [tag1, tag2]
compatibility:
  claude-code: true
  codex: true

Body Structure

# Skill Name

## Description (optional)
Expand on the frontmatter description if needed.

## Setup
Any prerequisites or configuration needed.

## Commands/Usage
How to use the skill.

## Examples
Concrete usage examples.

## Advanced
Link to references/ for detailed documentation.

Bundled Resources

Skills can include additional resources:

skill-name/
├── SKILL.md           # Required
├── references/        # Extended documentation
│   └── advanced.md
├── scripts/           # Executable code
│   └── helper.py
└── assets/            # Templates, files for output
    └── template.json

Best Practices

  1. Keep SKILL.md concise - Under 500 lines
  2. Front-load triggers - Put trigger phrases in the description
  3. Use references/ - Move detailed docs out of SKILL.md
  4. Provide examples - Concrete, copy-pasteable examples
  5. Document requirements - API keys, dependencies, etc.
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