Claude Code Plugins

A Claude Code plugin is a directory of skills, subagents, hooks and MCP servers that Claude Code installs and loads as one unit, usually from a marketplace; run /plugin in a session to browse and install, or claude plugin install <plugin>@<marketplace> from the shell (Plugins overview, read Nov 6, 2026). Anthropic launched plugins on Oct 9, 2025 as a way to package and share slash commands, subagents, MCP servers and hooks.

Quick facts

Sources for the table: Plugins overview, Install and manage plugins and Anthropic's marketplaces, Anthropic, read Nov 6, 2026.

What is inside a plugin?

A plugin folder holds a manifest at .claude-plugin/plugin.json (its name, plus an optional version and description) and its components: skills under skills/<name>/SKILL.md, subagent files under agents/, hooks in hooks/hooks.json, and MCP servers in .mcp.json. A plugin's skills run with its name as a prefix, so a review skill in my-plugin is /my-plugin:review (Plugins overview, read Nov 6, 2026).

0:00 Since Oct 1, 2026 a plugin can also carry a hooks module: JavaScript or TypeScript handlers that run inside Claude Code and can draw panes and bands, restyle its interface, step into tool calls and add commands that run without a Claude turn. A plugin with one is called a mod, and some built-in features such as /diff are themselves mods. Mods run in the terminal, the Code tab of the desktop app and the VS Code extension (Mods overview, read Nov 6, 2026).

How do you install a plugin?

1. In a terminal session, type /plugin and open the Discover tab, which lists the plugins of every marketplace you have added.
2. Pick a plugin, read what it adds, and choose a scope: user (you, every project on this computer), project (everyone in the repository, through the committed .claude/settings.json) or local (you, this repository only).
3. Or install directly: /plugin install commit-commands@claude-plugins-official in a session, or claude plugin install commit-commands@claude-plugins-official in the shell.
4. Turn one off without removing it with /plugin or claude plugin disable.

Source: Install and manage plugins, read Nov 6, 2026. A project-scope plugin is enabled for collaborators through settings, but each person still installs it on their own machine. A user-scope plugin installed in the terminal also appears in the desktop app's local sessions and in VS Code on that computer, while a cloud session at claude.ai/code does not load your local plugins (Plugins overview, read Nov 6, 2026).

Marketplaces

3:00 A marketplace is not a store but a catalog: a Git repository or folder with a .claude-plugin/marketplace.json file that lists plugins and where to fetch each. Add one with /plugin marketplace add <repo-or-url>, then install its plugins by name.

Anthropic runs two main ones. The official marketplace, claude-plugins-official, is added automatically the first time you start an interactive terminal session unless company policy blocks it. The community marketplace, claude-community, is not added on its own. Topic marketplaces such as anthropics/skills exist too, and the older claude-code-plugins marketplace in the anthropics/claude-code repository is deprecated (Anthropic's marketplaces, read Nov 6, 2026). Claude Code accepts the official and community names only from repositories under github.com/anthropics/, so a third-party catalog cannot pose as Anthropic's (Plugins overview, read Nov 6, 2026).

The plugin marketplaces are separate from Claude Marketplace, the website at claude.com/marketplace for browsing plugins, connectors and partners. On claude.ai and in Cowork, plugins use the same format but load a different set of components.

What does a plugin cost you?

An enabled plugin is part of every session, not only the ones where you use it. The name and description of each skill, agent and command Claude can start on its own sits in context every turn, which counts toward usage; its MCP servers run beside each session, and its hooks fire at their events. Plugins in the official marketplace show a Context cost estimate in /plugin, and the Installed tab groups plugins "Not used recently" so you can turn them off (Plugins overview, read Nov 6, 2026).

Security is the other cost. Whatever its marketplace, a plugin runs code with your user privileges, and Anthropic's mods page warns that a mod is code running with your permissions. Read a plugin's hooks and MCP servers before installing anything outside Anthropic's marketplaces; organizations can allowlist or block marketplaces and force-install plugins through managed settings (Plugins overview, read Nov 6, 2026).

How do you build a plugin?

1. Make a folder with .claude-plugin/plugin.json containing at least a name.
2. Add components: a skills/ folder, an agents/ folder, hooks/hooks.json, .mcp.json.
3. Load it straight from the folder while you work: claude --plugin-dir ./my-plugin (plugins also load from a .zip or a URL with --plugin-url, since May 4 to 8, 2026).
4. Measure it with claude plugin eval, which runs it against test cases and compares the result with no plugin (added Sep 7 to 11, 2026).
5. Share it by listing it in a marketplace of your own, or submit it to Anthropic's directory.

Sources: Plugins overview and What's new, read Nov 6, 2026. Skills, hooks, agents and MCP servers all work without a plugin; Anthropic suggests a plugin only when you want several of them packaged together, versioned or shared across projects.

Frequently asked questions

How do I install a Claude Code plugin? Type /plugin in Claude Code, open Discover, choose the plugin and a scope. From the shell, claude plugin install <plugin>@<marketplace> does the same, for example commit-commands@claude-plugins-official.

What is the Claude Code marketplace? A plugin marketplace is a catalog file (.claude-plugin/marketplace.json) in a repository that lists plugins. Claude Code adds Anthropic's official one, claude-plugins-official, on first start; you can add others with /plugin marketplace add.

Are Claude Code plugins safe? A plugin runs code with your own permissions, whichever marketplace it comes from. Anthropic advises reviewing a plugin's hooks, MCP servers and mod code before installing it, especially from third-party marketplaces.

Do plugins slow Claude Code down or use tokens? An enabled plugin adds each skill's and agent's name and description to context on every turn and runs its MCP servers in every session, which uses some tokens. Disable plugins you are not using with /plugin or claude plugin disable.

What is a Claude Code mod? A mod is a plugin with a hooks module: JavaScript or TypeScript code that runs inside Claude Code and can change its interface, add panes and commands, or step into tool calls. Mods arrived on Oct 1, 2026.

Sources

• Plugins overview, Anthropic, read Nov 6, 2026
• Install and manage plugins, Anthropic, read Nov 6, 2026
• Anthropic's marketplaces, Anthropic, read Nov 6, 2026
• Mods overview, Anthropic, read Nov 6, 2026
• What's new, Anthropic, read Nov 6, 2026
• Customize Claude Code with plugins, Anthropic, Oct 9, 2025
• Mods in Claude Code: change how Claude Code works, Claude, Oct 5, 2026 (video)