Overview

Skills are domain-specific knowledge modules that extend agent capabilities. Unlike tools (which provide actions), skills provide knowledge and context that guide how agents approach problems.

Skills = Knowledge (how to approach)
Tools  = Capabilities (how to execute)

Skill Structure

Each skill is a directory containing:

skills/
└── antigravity/
    ├── SKILL.md      # Frontmatter + instructions
    └── index.ts      # Tool definitions (optional)

SKILL.md Format

---
name: antigravity
description: Monitors and heals Antigravity IDE agent errors
---

# Antigravity Healer

You are a health monitor for the Antigravity IDE...

## Detection Rules
- Look for "Agent Terminated" errors
- Check cascade panel visibility

## Recovery Procedure
1. Call antigravity_check_and_heal
2. Report status

The frontmatter defines metadata, and the markdown body provides instructions injected into the agent’s system prompt.

Skill Tools

Skills can provide specialized tools via index.ts:

export function getTools() {
  return {
    antigravity_check_and_heal: {
      description: "Scan for errors and auto-recover",
      inputSchema: z.object({}),
      execute: async () => {
        // Domain-specific implementation
        return { status: "HEALTHY", message: "All good" };
      },
    },
  };
}

Using Skills

Skills are assigned to agents via configuration:

const agent = new Agent({
  name: "Healer",
  skills: ["antigravity"],  // Skill IDs
  tools: ["browser"],       // Separate from skills
});

Or in YAML job definitions:

name: Antigravity Healer
skills:
  - antigravity
tools:
  - browser
prompt: |
  Call antigravity_check_and_heal to monitor health.

Skills vs Tools

::: tip Skills encapsulate both knowledge (instructions) and specialized tools for a specific domain. This follows the “Atomic Skill-Level Healing” principle where detection and recovery are bundled together. :::

Built-in Skills

Creating Custom Skills

1. Create a directory under src/skills/:

   src/skills/my-skill/
   ├── SKILL.md
   └── index.ts

2. Define the SKILL.md with frontmatter and instructions

3. Optionally export tools from index.ts

4. Reference by skill ID in agent config