Writing Plugins

Scope: covers plugin design and architecture. The examples use the Claude Code layout (.claude-plugin/plugin.json + auto-discovered commands/, agents/, skills/, hooks/). The same artifact-selection and architecture reasoning maps to the other tools — only the manifest path and packaging differ:

• Codex CLI: .codex-plugin/plugin.json manifest + .agents/plugins/marketplace.json; skills live at .agents/skills/. See [[nlpm:conventions-codex]].
• Antigravity: gemini-extension.json (becoming "Antigravity plugins"); skills at .agent/skills/. See [[nlpm:conventions-antigravity]].
• Cross-tool skills: a SKILL.md collection with no plugin wrapper installs into any tool via npx skills add. See [[writing-skills]].

For individual artifact authoring, see [[writing-skills]], [[writing-agents]], [[writing-hooks]], [[writing-rules]].

1. Plugin = Commands + Agents + Skills + Hooks

A plugin is a collection of NL artifacts that work together. Before writing anything, decide which artifacts you need.

Artifact Selection Guide