Skill Artifacts

Use /prompt-principles for broader prompt design and loading strategy. This skill covers how skill artifacts are structured in Meridian.

A skill is a directory under skills/ with a SKILL.md and optional resources/, scripts/, and assets/ subdirectories. The description is the trigger surface. The body is the loaded instruction layer. resources/ carry deeper content. scripts/ are for deterministic operations that should run instead of being re-derived in context.

Loading

Skills reach agents through four paths (see /prompt-principles/resources/skill-level.md for design guidance):

• load: always in the system prompt. Use for skills the agent needs every run.
• available: agent can self-load when model-invocable: true. Use for skills it may reach for on demand.
• description: caller discovery surface. List attachable skill names so parent agents know what to compose via --skills.
• --skills: caller injection at spawn time. Bypasses available; any bundled skill can be injected.

model-invocable defaults to true; an explicit model-invocable: false makes an available skill visible but not self-loadable (caller injection via --skills still works). Keep the global model-invocable pool small; each entry costs description tokens on every turn.

Types

Set type: to declare the skill's role: principle for always-loaded thinking guidance, guardrail for always-loaded safety boundaries, mode-shift for on-demand shifts in activity, checkpoint for phase gates, reference for operational how-to.

Descriptions

Descriptions should lead with when to load the skill, not just what it contains. The description is what an agent or orchestrator reads to decide whether to load. "Load when reviewing test architecture" beats "Covers test structure patterns."