Plugins and marketplaces

A marketplace lists Claude Code plugins; installing a plugin adds its particular instructions or tools. Try one explanatory plugin in a practice project, check what it adds, and learn how to disable it.

Before you start

• A working, current Claude Code CLI with an interactive session. This guide uses the terminal plugin browser.
• A small practice project and a saved working copy. Pick a function you understand where adding a short comment will be easy to review.
• Permission to install local Claude Code plugins and network access to Anthropic’s official marketplace. Organization policy may restrict installation.
• Time to read the plugin’s details. The example explanatory-output-style plugin adds instructions and longer explanations, which can increase token use.

Want to do it yourself?

Difficulty

6 out of 10

Estimated completion time

30–60 minutes

Skills you’ll need: Inspect a plugin’s files and permissions, install it for one project, and compare behavior before and after disabling it.

I’ll do it myselfI’d rather get help

How this helps your brand

A carefully chosen explanatory plugin can help you understand the code you maintain. Checking its comments against the actual function supports informed updates rather than relying on plausible technical explanations.

1. 1

   Step 1: Open the official marketplace

   Start Claude Code in the practice project and run /plugin. The Discover tab lists plugins from the marketplaces registered on your machine. A marketplace is the catalog; a plugin is what you install from it.

   Open the Marketplaces tab and look for claude-plugins-official. If it is missing, run /plugin marketplace add anthropics/claude-plugins-official inside the session, then return to the plugin browser. Use the full source shown here; similarly named marketplaces can have different contents.

   Illustrated exampleA marketplace lists plugins; it is not the plugin

   ›/pluginopen the plugin browser

   DiscoverMarketplacesInstalled

   ⌘

   claude-plugins-officialMarketplace · catalog of available plugins

   Anthropic

   anthropics/claude-plugins-officialConfirm the full source

   lists

   Plugin · one installable itemexplanatory-output-styleInstructions added when a session starts

   Details ↗

   The marketplace is the catalog. The plugin is the package you inspect and install.

2. 2

   Step 2: Read the example plugin before installing

   Find explanatory-output-style in the official marketplace and open its details. Read its description and component list, then inspect its README if you need more context.

   This Anthropic plugin uses a SessionStart hook to add instructions for educational explanations about implementation decisions. It works when a session starts rather than exposing a command you must invoke. Other plugins can include skills, agents, hooks, and tool servers, so do not assume they behave the same way.

   A marketplace’s name alone does not tell you who wrote every plugin in it. Check the publisher and what will run. If this exact plugin is unavailable, stop this exercise and review another plugin’s own instructions before substituting it.

   Illustrated exampleThis plugin adds instructions when a session starts

   01Fresh sessionClaude Code opens in the practice repo

   →

   02SessionStart hookLoads the plugin’s explanation instructions

   →

   03Small code taskAsk for one comment; inspect every changed line

   Component list · inspect before installexplanatory-output-style

   HookSessionStartRuns as a session begins

   Also possibleSkills

   Also possibleAgents

   Also possibleTool servers

   ✓

   Instructions guide the response; they do not verify it. Compare the explanation with the actual code before keeping the comment.

3. 3

   Step 3: Install it for this project only

   Choose Install for you, in this repo only, the local scope. User scope makes a plugin available across your projects on this machine; project scope enables it for collaborators through the repository’s settings.

   Read the install summary and open the Installed tab to confirm the name and scope. If loading fails, read the Errors tab. If a reload is requested, follow the displayed instruction. For this SessionStart example, begin a fresh session in the same project before testing it.

   Illustrated exampleMatch the install scope to who needs access

   Install destinationChoose who should get this pluginFor this exercise, use the narrowest scope: only this repo on this machine.

   01

   UserAvailable across your projects

   This machine

   02

   LocalOnly this repository, for you

   Practice choice

   03

   ProjectEnabled for collaborators

   Repo settings

   Install for you ⌄Read the summary, then confirm the name and scope in Installed.

4. 4

   Step 4: Test one small change

   Paste the prompt below in the fresh session. Ask for a short comment explaining a function you selected, with no behavior change. Keep the task small enough to inspect every changed line.

   Look for educational insights tied to the implementation and compare them with the actual code. The plugin asks Claude to explain its choices; it does not certify those explanations. Check that the only file change is the requested comment.

   If you see no effect, confirm the plugin is enabled for this repository and start a new session after installation. If an explanation is inaccurate, correct it before keeping the comment.

5. 5

   Step 5: Disable the plugin and compare

   Run /plugin, open Installed, select the plugin, and disable it. Start another fresh session so its startup instructions are no longer added there. Compare a similar small task if you want to judge whether the extra explanations are useful.

   You can uninstall the plugin from Installed when finished. Disabling or uninstalling does not review or reverse the code edits from your test; compare those separately with your saved copy.

In this practice project, add one concise comment explaining [function name] in [file path] for a beginner. Preserve the function’s behavior and change no other files. Explain the implementation choices in terms of this actual code. Do not invent a purpose the code does not demonstrate. If the function is missing or ambiguous, ask me to identify it. Finish with the exact file change, a short explanation, and any checks you actually performed. Do not commit, push, or publish.