What is a Skill?
A skill is a self-contained, versioned capability that extends what an AI agent can do. Skills are defined by a single SKILL.md file — a markdown document with YAML frontmatter that describes the skill’s identity, purpose, trigger conditions, and execution instructions.
The Hordago runtime discovers skills at session start, matches user intent against skill triggers, and invokes the relevant skill’s instructions when conditions are met.
The SKILL.md Contract
Every skill is a SKILL.md file at the root of its directory. The runtime reads this file and extracts two things:
- Frontmatter — structured metadata (title, trigger, version, author, etc.)
- Body — freeform markdown instructions the agent follows when the skill is active
---
name: my-skill
title: "My Skill"
description: "What this skill does in one sentence."
version: "1.0.0"
author: "your-github-handle"
trigger: "Use when the user asks to do X or Y."
---
# My Skill
Instructions for the agent go here. Be specific about:
- What inputs to expect
- What steps to take
- What output to produceHow Skills Are Invoked
Skills are invoked in two ways:
- Explicit — the user types
/skill-nameas a slash command - Implicit — the runtime matches the user’s intent against each skill’s
triggerfield and auto-activates the best match
Once active, the skill’s body becomes the agent’s operating instructions for that task.
Skills vs. Prompts vs. Plugins
| Concept | Purpose | Scope |
|---|---|---|
| Skill | Defines reusable agent behavior | Single capability |
| Plugin | Bundles multiple skills + MCP tools | Full feature set |
| Prompt | One-off instructions | Single conversation turn |
Skills are the atomic unit. Plugins are collections of skills. If you’re building a focused capability, start with a skill.
Next Steps
Ready to build your first skill? Head to the 10-minute quickstart.