Writing Skills

Build reusable skills with triggers, workflows, and validation layers.

Skill Anatomy

A skill is a directory under skills/ with a SKILL.md whose frontmatter declares name and description. Larger skills add supporting playbooks, for example the bundled debugging skill:

• SKILL.md — frontmatter (name, description) plus the routing logic
• common.md, ci-cd.md, codebase.md, frameworks.md — focused playbooks
• checklists/, validation/ — deterministic quality gates

Trigger Design

The description frontmatter drives auto-triggering — define explicit trigger phrases and decision boundaries.

Trigger when the user asks for "review this PR" or shares a diff.
When in doubt, use this skill.

The bundled skill-writer skill automates this: invoke /nexus:skill-writer to create or refine a skill's structure and triggers.

Quality Gate

Every skill should include deterministic output validation rules.