Writing a good skill

A 3B skill is an Agent Skills bundle the AI loads on demand. Each skill is a directory with a required SKILL.md and optional supporting files:

my-skill/
├── SKILL.md
├── references/
│   └── api.md
├── assets/
│   └── report-template.md
└── scripts/
    └── collect.ts

SKILL.md starts with YAML frontmatter. name and description are required. The name uses lowercase letters, numbers, and single hyphens, and it matches the parent directory. license, compatibility, string-valued metadata, and the experimental allowed-tools field are optional. allowed-tools is guidance, not a grant of 3B permissions. The body contains the instructions the AI reads once the skill is in play.

The description is the trigger