Install, enable, and verify plugins

What you can install#

Plugins package Skills, Agents, hooks, or MCP servers. This walkthrough uses Frontend Design, published by Anthropic in the official claude-plugins-official marketplace. It supplies a frontend-design Skill; it is not Onevium's built-in Widget tool. See the official plugin description.

Open plugin management#

Click Plugins in the left sidebar. The page brings Plugins, Skills, and MCP together. Use the scope selector to choose a project or Personal · all projects before installing or changing an entry. Personal plugins can be available across projects unless disabled in a project; selecting a project does not hide every inherited capability.

The Claude Code marketplace is integrated into the Plugins tab. Find the Claude Code plugins section and click Browse marketplace. This section uses your existing Claude environment and is independent of the project scope selector; check the installed entry’s Scope rather than assuming project-only installation.

The marketplace list comes from catalogs already downloaded in that environment. A listed plugin is not necessarily installed. You need a working model connection to use its Skill after installation.

Install Frontend Design#

1. In Plugin marketplace, click the Search plugins… icon and search for frontend-design.
2. Check the source is claude-plugins-official and the author is Anthropic. The full identifier is frontend-design@claude-plugins-official.
3. Click Install, then Back to plugins. Check that it appears in the Claude Code plugins section.
4. Open its details. Check Source, Scope, and the supplied Skills; switch it on if disabled.
5. Start a new conversation in a small frontend project so the runtime can load the plugin.

If the official marketplace is missing#

A marketplace address and a downloaded catalog are different. Open Manage sources in the marketplace to add an address. Add marketplace records the address; that button alone does not download the catalog.

If you use a Claude Code CLI configured for the same user and configuration directory as Onevium, register or refresh the official catalog there:

claude plugin marketplace add anthropics/claude-plugins-official
claude plugin marketplace update claude-plugins-official

Run the add command only if the marketplace is absent. Reopen Browse marketplace, search again, and continue when the actual listing appears. These are terminal commands, not promises that every upstream slash command works in Onevium chat. The official marketplace guide explains registration and refresh.

Try the installed Skill#

In the new conversation, ask for a small artifact:

Use the frontend-design Skill from frontend-design@claude-plugins-official.
Create demo-settings.html with a compact notification-settings panel.
Include labels, a save button, and an empty state; use fictional data.
Write only this demo file, then show how to preview it.

Check that the Skill is invoked or read, that its source is the official plugin, and that the file opens. The plugin is a Skill-based workflow; a separate slash command is not required. Keep the demo file separate from your app until you decide to integrate it.

Enable, inspect, and uninstall#

In the unified plugin center, open a plugin and check its source, version, included capabilities, and selected scope. Enable or disable it for that scope. Remove from this scope removes the scope’s selection; stored versions can remain available to other projects and running tasks. Start a new run to verify a change; an existing run keeps its loaded context.

When an update is available, review it and choose the update action for the selected scope. Checking for updates does not install them automatically. Updates preserve the current enabled or disabled state, and running tasks keep their version.

For the Claude Code plugins section used in this walkthrough, the controls remain enable/disable and Uninstall with confirmation. This section has no dedicated plugin update button; update through the matching Claude CLI environment, then reload and check the version. Claude Code plugins and the other plugins in the center have different scope and update controls.

Solve common problems#

Next steps#

Learn Skills, connect an MCP server, or use the workflow tips to choose between built-in tools and installed capabilities.