Claude skill plugin packaging

Claude Code Skill Plugin Packaging

When to invoke

• You have skills in one repo and want them reusable across other repos/projects.
• Wiring an existing skill plugin (e.g. apple-dev-skills) into a new project.
• Deciding flat project skills vs a plugin.
• A submodule/nested folder of skills "isn't being discovered" and you don't know why.
• Aggregating other people's skill repos without copy-pasting.
• User asks "how do I share/install skills", "why is my .claude/skills/<lib>/... not found".

The one rule that explains everything: discovery is depth-1

Claude Code discovers plain project skills only at depth 1: .claude/skills/<skill>/SKILL.md. It does not recurse into subdirectories.

Consequences (each has burned someone):

• A git submodule of skills at .claude/skills/<lib>/ puts SKILL.md at .claude/skills/<lib>/skills/<skill>/SKILL.md (depth ≥ 2) → NOT discovered.
• A bare folder of skills nested one level down → NOT discovered.
• An in-repo submodule of a plugin you also installed via a marketplace is vestigial — the marketplace-installed copy is what loads, the submodule does nothing for discovery. (This is why a repo can carry .claude/skills/superpowers yet superpowers actually loads from the plugin cache.)

So: to share skills across repos, package them as a plugin and distribute via a marketplace. A bare submodule alone never works.

Packaging: make your skills a plugin + marketplace

A repo becomes a Claude Code plugin with a manifest, and a marketplace (catalog) with a second manifest. One repo can be both (single-repo model):

your-skills-repo/
├── .claude-plugin/
│   ├── plugin.json        # makes it a plugin; "name" becomes the namespace
│   └── marketplace.json   # makes it a marketplace; lists plugins
└── skills/
    └── <skill>/SKILL.md   # one dir per skill

plugin.json (the name is the plugin namespace prefix — skills surface as plugin-name:<skill>; this is independent of the marketplace name):

{ "name": "your-skills", "version": "0.1.0", "description": "…", "license": "MIT" }

The marketplace name is the catalog identifier used in /plugin install plugin-name@marketplace-name. These are two distinct names that happen to be the same string in the single-repo model — that identity is a coincidence, not a requirement. A real-world example where they differ: "code-formatter@company-tools" (plugin name = code-formatter, marketplace name = company-tools).

marketplace.json — lists this plugin (and can list MANY plugins from other sources):

{
  "name": "your-skills",
  "owner": { "name": "you" },
  "plugins": [
    { "name": "your-skills", "source": "./", "description": "…", "version": "0.1.0" }
  ]
}

"source": "./" = the plugin is at the marketplace repo root.

Installing (consuming) into a project — three models

A. Global marketplace (simplest, latest)

/plugin marketplace add owner/your-skills-repo
/plugin install your-skills@your-skills

Loads globally (every project), namespaced. Not pinned per repo.

B. Vendored submodule + project-scope committed settings (pinned, git-tracked, "comes with the project")

This is the recipe when a specific repo must depend on a pinned version, reproducibly, with no manual install for collaborators.

1. Vendor + pin:

   git submodule add https://github.com/owner/your-skills-repo.git .claude/skills/your-skills
   cd .claude/skills/your-skills && git checkout v0.1.0 && cd -
   

2. Commit this to the project's .claude/settings.json (the shared, committed file — not .claude/settings.local.json, which is personal/gitignored):

   {
     "extraKnownMarketplaces": {
       "your-skills": {
         "source": { "source": "directory", "path": "./.claude/skills/your-skills" }
       }
     },
     "enabledPlugins": { "<plugin-name>@<marketplace-name>": true }
   }
   

   Replace <plugin-name> with the name from the plugin's plugin.json and <marketplace-name> with the name from the marketplace's marketplace.json. In the single-repo model these happen to be the same string (e.g. "your-skills@your-skills": true), but they are conceptually distinct — the plugin namespace and the catalog identifier.
   • The marketplace source for a local dir is an object {"source":"directory","path":"./relative"} — a relative path (resolves against the repo's main checkout). A relative path only resolves because the submodule is itself a git repo.
3. On git clone --recurse-submodules + workspace-trust, Claude Code auto-registers the marketplace and enables the plugin. Skills load as your-skills:<skill>. No /plugin install step.

Why both pieces: the submodule pins the exact version (a commit SHA); the committed settings.json is what actually makes Claude Code load it. Either alone is insufficient (submodule-only = not discovered; settings-only = nothing to point at).

C. npm — a packaging path some skill sets use (npx …); out of scope here.

Aggregating other skill repos (don't reinvent)

A marketplace is a catalog of plugins from many sources — that is the native aggregation mechanism, no submodule required. Add more entries to plugins[], each with its own source:

"plugins": [
  { "name": "your-skills",        "source": "./" },
  { "name": "someones-testing",   "source": { "source": "github", "repo": "them/testing-skills" } },
  { "name": "vendored-thing",     "source": { "source": "git-subdir", "url": "https://…", "path": "tools/plugin" } }
]

Accepted plugin sources: relative "./path" (within the marketplace repo, must start with ./), github (repo,ref?,sha?), url (git URL), git-subdir (url,path), npm (package,version?). Use a submodule only when you need to vendor + pin another repo's content into yours.

Gotchas (verified)

• Bare submodule of skills ≠ discovered (depth-1 rule). Always pair with a plugin manifest + marketplace registration.
• @skills-dir auto-load (a plugin folder under .claude/skills/ loading without registration) is documented but not reliably in use — don't depend on it; register a marketplace.
• git commit -a skips new files — plugin.json/marketplace.json are new; -a will silently omit them. Use explicit git add and verify with git show --stat.
• Marketplace state is per-user (~/.claude/plugins/known_marketplaces.json), but the committed project .claude/settings.json declaration is what makes it reproducible for everyone on trust.
• Token cost: every enabled skill's description is always-on context. ~25 skills ≈ a few thousand tokens per session. Keep the set curated.
• Relative marketplace paths only resolve when the marketplace is a git repo (a submodule qualifies); a direct-URL marketplace can't resolve relative plugin sources.

Verification

• /reload-plugins then check the skills list shows your-skills:<skill> entries.
• claude plugin details your-skills@your-skills lists the bundled skills + scope.
• For model B: git ls-files .claude/settings.json (it's committed) and the submodule gitlink point at the intended version.