Four mechanisms, four different jobs
| Type | What it provides | Pick it for |
|---|---|---|
| Skill | Instructions centered on SKILL.md | Repeatable task knowledge or a workflow |
| Settings hook | Event-triggered logic configured in settings | An existing script or handler at a lifecycle event |
| Mod | JavaScript or TypeScript handlers inside Claude Code | UI panes, custom commands or event rewriting |
| MCP server | Tools from an external service or process | Reaching documentation, browsers or repositories |
A plugin is a packaging layer around these components. It can ship more than one type. A subagent adds a specialized delegation role and is another distinct component you can bundle.
Choose from the outcome you want
“Use our design conventions when building a page.”
A skill is the natural starting point: it supplies instructions relevant to frontend work. Frontend Design demonstrates this instruction-led approach.
“Show how full the context window is above my prompt.”
A mod can read session events and draw a band in a supported surface. Token Weather demonstrates that pattern, with specific terminal and history limitations.
“Warn when a matching tool action occurs.”
A settings hook or a rule-based package may fit. Hookify creates readable pattern rules. If you also need a custom interactive preview, Blast Radius demonstrates a mod handler and pane.
“Look up documentation for the version I use.”
An MCP integration exposes external lookup tools. Context7 provides a hosted documentation connection. Your queries reach an external service.
Execution and trust matter
A skill is instructions, but it can direct tool use. A settings hook runs configured logic. A mod runs with your privileges inside Claude Code. An MCP tool can act in the system behind its server. Choosing a type does not remove the need to read source, inspect permissions and understand effects.
Drawing is especially surface-dependent: a mod can run hooks in a session that does not display its custom UI. Follow the official surface table and the particular sample’s requirements.
Choose a package after choosing the type
Use the comparison tool for up to three documented entries. It compares requirements and tradeoffs rather than claiming a benchmark winner.