What are skills

(Source: https://agentskills.io/what-are-skills)
Agent Skills are a lightweight, open format for extending AI agent capabilities with specialized knowledge and workflows.

At its core, a skill is a folder containing a SKILL.md file. This file includes metadata (name and description, at minimum) and instructions that tell an agent how to perform a specific task. Skills can also bundle scripts, templates, and reference materials.

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

Skills use progressive disclosure to manage context efficiently:

1. Discovery: At startup, agents load only the name and description of each available skill, just enough to know when it might be relevant.
2. Activation: When a task matches a skill’s description, the agent reads the full SKILL.md instructions into context.
3. Execution: The agent follows the instructions, optionally loading referenced files or executing bundled code as needed.

This approach keeps agents fast while giving them access to more context on demand.

Every skill starts with a SKILL.md file containing YAML frontmatter and Markdown instructions:

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---
name: pdf-processing
description: Extract text and tables from PDF files, fill forms, merge documents.
---

# PDF Processing

## When to use this skill
Use this skill when the user needs to work with PDF files...

## How to extract text
1. Use pdfplumber for text extraction...

## How to fill forms
...

The following frontmatter is required at the top of SKILL.md:

• name: A short identifier
• description: When to use this skill

The Markdown body contains the actual instructions and has no specific restrictions on structure or content.This simple format has some key advantages:

• Self-documenting: A skill author or user can read a SKILL.md and understand what it does, making skills easy to audit and improve.
• Extensible: Skills can range in complexity from just text instructions to executable code, assets, and templates.
• Portable: Skills are just files, so they’re easy to edit, version, and share.