harness:writing-skills

To write process documentation agents reliably follow, use a TDD-based authoring method that defines triggering conditions, enforces iron rules, and validates agent compliance using eval scenarios before deployment.

The best way to make Claude Code discover custom skills is adding CSO-friendly YAML frontmatter with harness namespacing, triggering conditions, symptoms, and keywords to your instruction documents.

You validate new skills by running baseline-vs-with-skill eval scenarios and applying structure requirements to verify agents comply with the rules instead of rationalizing behavior.

YAML frontmatter fails discovery checks when description text avoids workflow summaries, lacks the Use when prefix, or misses harness namespacing required for CSO discovery metadata compliance.

You need eval coverage for skill authoring changes when required by the harness eval and checklist workflow, enforcing vendoring discipline so commits include corresponding eval validation.