Marketplaces & Plugins - Spotify for Backstage

Plugins and marketplaces are the distribution mechanism for skills. While individual skills and rules can be discovered in AI Explorer on their own, plugins and marketplaces let you group, version, and distribute collections of skills as installable packages.

Key concepts

A marketplace is a Git repository that hosts one or more plugins
A plugin wraps one or more skills into a single installable package
A skill is a directory containing a SKILL.md file (see Skills)

You don’t need a plugin or marketplace for your skill to appear in AI Explorer as a standalone SKILL.md in any scanned repository is enough for discovery. But wrapping skills in a plugin and publishing through a marketplace makes distribution and installation easier.

How discovery works

AI Explorer automatically scans configured GitHub organizations for these files:

File	Location	Entity type
`SKILL.md`	Any directory	Skill
`plugin.json`	`.claude-plugin/plugin.json`	Plugin
`marketplace.json`	`.claude-plugin/marketplace.json`	Marketplace

Creating a plugin

A plugin is defined by a plugin.json file at .claude-plugin/plugin.json in your repository:

{
  "name": "my-team-essentials",
  "version": "1.0.0",
  "description": "Essential skills for the backend team",
  "author": { "name": "backend-team" },
  "skills": ["skills/database-migrations", "skills/api-endpoint-creator"]
}

Plugin fields

Field	Required	Description
`name`	Yes	Plugin name
`description`	No	Short description
`version`	No	Semantic version
`author`	No	Author info (`{ "name": "..." }`)
`skills`	No	Paths to skill directories containing a `SKILL.md`

If skills is omitted, the plugin automatically discovers SKILL.md files under skills/ relative to the plugin root.

Creating a marketplace

A marketplace is defined by a marketplace.json file at .claude-plugin/marketplace.json in your repository:

{
  "name": "backend-marketplace",
  "description": "Backend team's curated plugins",
  "version": "1.0.0",
  "owner": { "name": "backend-team" },
  "plugins": [
    {
      "name": "my-team-essentials",
      "source": "./plugins/my-team-essentials",
      "description": "Essential skills for the backend team"
    },
    {
      "name": "data-pipeline-tools",
      "source": "./plugins/data-pipeline-tools"
    }
  ]
}

Marketplace fields

Field	Required	Description
`name`	Yes	Marketplace name
`description`	No	Short description
`version`	No	Semantic version
`owner`	No	Owner info (`{ "name": "...", "email": "..." }`)
`plugins`	No	List of plugin entries (see below)
`metadata`	No	Fallback `description` and `version` if not set above

Plugin entry fields

Each entry in the plugins array describes a plugin to include in the marketplace:

Field	Required	Description
`name`	Yes	Plugin name
`source`	Yes	Relative path (e.g. `./plugins/my-plugin`) or a source object (see below)
`description`	No	Short description
`version`	No	Semantic version
`skills`	No	Paths to skill directories within the plugin

Plugin sources

The source field supports two forms: Relative path — references a plugin directory within the same repository:

{
  "name": "my-plugin",
  "source": "./plugins/my-plugin"
}

If a .claude-plugin/plugin.json exists at that path, the marketplace links to it. Otherwise, AI Explorer creates a plugin entity from the marketplace entry itself. GitHub repository — references a plugin in a different repository:

{
  "name": "external-plugin",
  "source": { "source": "github", "repo": "my-org/external-plugin-repo" }
}

Installing from a marketplace

Once a marketplace is added to AI Explorer, its plugins appear in the Plugins tab. From a plugin’s detail page, the install card shows the commands to add the marketplace and install the plugin.

Browsing

In the Portal UI, navigate to AI Explorer:

The Skills tab shows all discoverable skills, including those within plugins
The Plugins tab shows all plugins, grouped by marketplace
Each plugin detail page lists its skills and provides install instructions

​Key concepts

​How discovery works

​Creating a plugin

​Plugin fields

​Creating a marketplace

​Marketplace fields

​Plugin entry fields

​Plugin sources

​Installing from a marketplace

​Browsing