Authoring artifacts

Reference for writing artifacts. Each page below covers one topic.

Page	What it covers
Your first skill	Continues the quickstart's greet skill: fuller frontmatter, a body reference to the bundled script, runtime requirements, watch mode, and lint.
Your first command	A parameterized slash command the user invokes by name. Argument substitution and how the command lands in the harness's slash menu.
Your first agent	A complete agent definition: minimal end-to-end version first, then runtime requirements, a bundled script, and a delegated artifact.
Artifact types	Built-in types: skill, agent, context, command, rule, hook, mcp-server.
Frontmatter reference	Field-by-field reference for the YAML frontmatter in ARTIFACT.md (and, for skills, SKILL.md).
Domains	How folders and subfolders structure the catalog, and how DOMAIN.md adds descriptions, keywords, featured artifacts, the prose body, and discovery rendering knobs.
Rule modes	The rule_mode values (always, glob, auto, explicit) and how each harness honors them.
Hooks	Lifecycle observers with hook_event and hook_action.
Extends	Cross-layer inheritance with extends:.
Bundled resources	Scripts, references, assets, and other files that ship alongside ARTIFACT.md (and SKILL.md for skills).
Hints	Advisory metadata: effort_hint and model_class_hint.

The three "Your first ..." walkthroughs are the foundation. The pages that follow are topic-specific reference.