> ## Documentation Index > Fetch the complete documentation index at: https://docs.rubixkube.ai/llms.txt > Use this file to discover all available pages before exploring further. # Plugins and marketplaces > Install bundles of skills, slash commands, agents, hooks, MCP servers and chat channels in one step, from a marketplace, GitHub, a git URL or a folder. See everything a plugin runs before it runs. A plugin bundles skills, slash commands, specialist agents, hooks, MCP servers and chat channels into one thing you install, update or remove together. Install one from a marketplace, a GitHub repository, a git URL or a folder on your machine. Nothing in it runs until you have seen what it contains. ## Ask Kepler for one Say what you need after `/plugins`: ``` /plugins something for terraform reviews ``` Kepler lists what you already have, searches the marketplaces you added, and proposes an install. `/plugins` on its own tells you what is installed and what is worth adding. Kepler can look at plugins in any posture. It can propose installing, updating, switching, removing a plugin or adding a marketplace only in Assist and Yolo, and each of those waits for you to confirm a card, Yolo included. The install card lists the plugin's hooks and MCP servers with the exact commands they run, then its skills, commands and agents. ## Install from Settings Open **Settings > Customize**, pick the **Plugins** chip, and choose **Add plugin**. The browser has two ways in: * **Marketplaces.** Add a marketplace once, as `owner/repo`, a git URL or a folder, and browse it any time with search and its categories. Kepler keeps a local copy. **Refresh** fetches it again. Removing a marketplace keeps the plugins you installed from it. * **From a link.** Install one plugin from a GitHub `owner/repo`, a git URL or a folder. Before anything is installed you see what the plugin contains: its hooks and MCP servers with the exact commands they run, then its skills, commands and agents. Parts Kepler does not run yet are listed too. Each installed plugin has a switch and a menu with **Settings** (when the plugin asks for any), **Check for update** and **Remove**. ## What a plugin adds | Part | Where it shows | Its name | | - | - | - | | Skills | **Customize > Skills**, under the plugin | `plugin:skill` | | Commands | The `/` menu, and **Customize > Commands** | `/plugin:command` | | Agents | **Customize > Agents**. Kepler can delegate to them. | `plugin:agent` | | Hooks | **Customize > Hooks** | As written | | MCP servers | **Settings > Tools & MCP**, tagged with the plugin's name | As written. A server of yours with the same name wins. | | Channels | **Settings > Gateway**, tagged with the plugin's name | See [Channels](/kepler/channels#add-a-channel) | Plugin items are read-only. Switch a skill or hook off, or update the plugin, to change it. A plugin's agents keep to the chat's posture. An agent that asks for shell or file tools can still change nothing in Observe. ## Plugin settings A plugin can ask for settings, such as a region, a URL or a token. Those plugins get a **Settings** action. Values marked sensitive go to your operating system keychain and are never shown again, only "Saved". A channel's own settings, such as its bot token, are asked for when you connect it on the Gateway page. ### Servers that need a sign-in A plugin's MCP server that signs in through your browser is listed in **Settings > Tools & MCP**, tagged with the plugin's name, and shows **Sign in** until you press **Connect** on its row. The install card, an update, and `/plugins` say which of a plugin's servers still need a sign-in. A plugin can declare the sign-in in its `.mcp.json` the way Claude Code reads it, with an `oauth` block: ```json theme={null} { "mcpServers": { "tracker": { "type": "http", "url": "https://mcp.tracker.example.com/mcp", "oauth": { "clientId": "abc123", "callbackPort": 3119, "scopes": "read write" } } } } ``` * `clientId` is an app the vendor registered. With one, Kepler skips registering an app of its own. * `callbackPort` is the local port the sign-in returns to. `scopes` is one space-separated string. * A server that declares nothing is asked whether it needs a sign-in, the same as one you add yourself. * Where Kepler has its own registered app for a server, such as Slack's, it signs in with that one instead, so the consent page names Kepler. A client you declare in your own `~/.kepler/mcp.json` still wins. * A malformed or unsupported `oauth` block shows **Config error**, and that server does not start. ## Trust * Nothing changes without you. Kepler can only propose, and every change waits for your card. * Kepler keeps its own copy of each plugin and records a fingerprint of its files. If those files change on disk afterwards, the plugin stops loading and shows **Changed on disk** until you review it again. Kepler's own file tools cannot write there. * **Check for update** fetches the source again. A change comes back as a review, and nothing changes until you approve it. * Plugin hooks follow the same rules as yours: they can block or ask, never approve, and commands on the [always-blocked list](/kepler/permissions#always-blocked) are refused. ## Make a plugin A plugin is a folder: ``` my-plugin/ .kepler-plugin/plugin.json name, description, version, settings, channels skills/ commands/ agents/ hooks/hooks.json .mcp.json ``` `plugin.json` is optional. Without it, Kepler reads the folders above by name. A marketplace is a repository with `.kepler-plugin/marketplace.json` listing its plugins. Inside the plugin, `${KEPLER_PLUGIN_ROOT}` is the plugin's folder and `${KEPLER_PLUGIN_DATA}` is a folder for its own state, deleted with the plugin. Hook commands and MCP servers also get both as environment variables. A setting the plugin asks for is filled into its MCP servers as `${user_config.KEY}` and reaches its hooks as `KEPLER_PLUGIN_OPTION_`. To give a plugin an icon, add `logo` or `icon` to its manifest, or put `assets/logo.svg` (or `.png`) in the plugin folder. SVG, PNG, JPEG and WebP up to 256 KB work. ### Plugins made for other agents Kepler also installs plugins and marketplaces in the Claude Code and Cursor formats. When a plugin has no `.kepler-plugin/` folder, Kepler reads `.claude-plugin/`, then `.cursor-plugin/`. The contents are the same format. Plugins you already installed for Claude Code on this machine are listed under **From Claude Code** with an **Import** button. ## Where things live | Path | What | | - | - | | `~/.kepler/plugins//` | The installed copy. | | `~/.kepler/plugin-data//` | The plugin's own state. Deleted with the plugin. | | `~/.kepler/plugins.json` | What is installed, from where, on or off, and your marketplaces. | | `~/.kepler/plugin-marketplaces//` | The local copy of each marketplace you added. | ## Where to go next Where plugins and everything they bring are managed. What a plugin's hooks can and cannot do. Plugins that bring a new chat channel. Integrations, skills, commands and specialists. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.