Advanced 6 concepts to know first · leads to 1

Plugins

A directory of skills, subagents, hooks and MCP servers that Claude Code installs and loads as one unit, usually from a marketplace, so a whole setup can be shared with one command.

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Know these first

6 concepts · basics first
  1. Context

    The context window is everything Claude can see in a session: your messages, the files it reads, tool output and auto-loaded instructions. It fills as you work, and Claude Code compacts it when it gets full.

  2. Hooks

    Your own commands that Claude Code runs automatically at fixed points in its loop, so a rule always holds instead of depending on the model remembering it.

  3. MCP

    The Model Context Protocol connects Claude Code to outside tools and data, such as an issue tracker, a database or Figma, through servers that hand Claude new tools to call.

  4. Slash Commands

    Type / to run a command: built-ins that control the Claude Code session itself, plus prompts packaged as skills, plugin commands and MCP prompts, including ones you write yourself.

  5. Memory

    CLAUDE.md files you write and auto memory notes Claude writes for itself: plain markdown on disk, loaded at the start of every session so Claude doesn't start from zero.

  6. Skills

    A SKILL.md file of instructions that Claude loads only when a task calls for it, or that you run yourself as a /command. Custom slash commands are now skills.

  7. Plugins · you are here

Skills, subagents, hooks and MCP servers all work on their own. A plugin is how you package several of them into one directory, so that someone else can install your whole setup with one command, and you can version it and update it in one place.

If all you have is one skill for yourself, you don’t need a plugin. Reach for one when you want to share a set of pieces with a team, or install a set someone else built.

What’s inside

A plugin is a folder with a manifest at .claude-plugin/plugin.json, which gives it a name, plus whichever components it needs:

  • skills/review/SKILL.md: a skill, run as /my-plugin:review.
  • agents/reviewer.md: a subagent Claude can delegate to.
  • hooks/hooks.json: hooks that fire on lifecycle events.
  • .mcp.json: MCP servers that connect while the plugin is enabled.

Plugins can carry more, including LSP servers, output styles and older-style commands/ files; the components page lists every type. Plugin skills are namespaced by the plugin’s name, so two plugins can both have a review skill without colliding.

Where they come from

Most plugins come from a marketplace: a repo or folder whose .claude-plugin/marketplace.json lists plugins and where to fetch each. It’s a catalog, not a hosted store. Claude Code adds Anthropic’s official marketplace the first time you start an interactive session.

Run /plugin to browse and install, or from your shell:

claude plugin install commit-commands@claude-plugins-official
claude plugin marketplace add your-org/plugins

You install at a scope: user (you, every project), project (everyone in the repo, through the committed .claude/settings.json), or local (you, this repo only).

The catch

An enabled plugin is part of every session, not only the ones where you use it. The name and description of each skill and agent Claude can invoke sit in context on every turn, its MCP servers run alongside the session, and its hooks fire at their events. And whatever a plugin runs, it runs as you. Read a plugin before you install it, and disable the ones you’ve stopped using.

Where it sits

Before this

Skills Hooks MCP
Plugins

Leads to

Mods

Sources

  1. Plugins overview . Claude Code docs: what a plugin is, marketplaces, install scopes, per-session cost
  2. Add components to a plugin . Claude Code docs: every component type and where its files go
  3. Install and manage plugins . Claude Code docs: /plugin, marketplaces, claude plugin install

Verified against the official Claude Code docs on October 1, 2026 · next review by January 1, 2027. Claude Code changes quickly; the docs are the source of truth.