Skill definition syntax

Updated May 06, 2026

A shared skill source is a directory under:

$XDG_DATA_HOME/repo-local-tools/skills/<name>/

Every skill should contain a SKILL.md file. The upstream Anthropic skill format uses YAML frontmatter for discovery metadata followed by Markdown instructions:

---
name: reviewer
description: Review changes for correctness, risk, and missing tests.
---

# Reviewer

Use this skill when reviewing a code change before it is merged.

The important parts are:

  • name: The skill identifier. Anthropic's guidance requires lowercase letters, numbers, and hyphens.
  • description: A concise trigger description that tells the agent when the skill is relevant.
  • Markdown body: The instructions, examples, scripts, and references the agent may load progressively when the skill is used.
  • Extra files: Optional scripts, references, templates, fixtures, or assets that belong with the skill directory.

repo-local-tools copies the directory as-is into each supported repo-local client skill location:

.claude/skills/<name>/
.codex/skills/<name>/
.factory-droid/skills/<name>/
.cursor/skills/<name>/