Claude Code Plugin & Marketplace Conventions

Best practices for creating, structuring, and distributing Claude Code plugins and marketplaces, based on official documentation and the anthropics/claude-plugins-official repository.

Plugin Directory Structure

plugin-name/
├── .claude-plugin/
│   └── plugin.json          # Manifest (ONLY this file here)
├── commands/                 # Slash commands (.md)
├── agents/                   # Subagent definitions (.md)
├── skills/                   # Skills (subdirectories with SKILL.md)
│   └── skill-name/
│       ├── SKILL.md
│       ├── scripts/
│       ├── references/
│       └── examples/
├── hooks/
│   ├── hooks.json            # Hook configuration
│   └── scripts/              # Hook scripts
├── .mcp.json                 # MCP server definitions
├── .lsp.json                 # LSP configurations
├── settings.json             # Default settings
├── scripts/                  # Shared utilities
├── LICENSE
└── README.md

Critical rules:

• .claude-plugin/ contains ONLY plugin.json — never nest components inside it
• All component directories at plugin root level
• Kebab-case for all directory and file names
• Only create directories for components actually used

plugin.json Schema

Minimal (auto-discovery handles the rest)

{
  "name": "plugin-name"
}

Recommended

{
  "name": "plugin-name",
  "version": "1.0.0",
  "description": "Brief plugin description",
  "author": {
    "name": "Author Name",
    "email": "author@example.com",
    "url": "https://github.com/author"
  },
  "repository": "https://github.com/author/plugin",
  "license": "MIT",
  "keywords": ["keyword1", "keyword2"]
}

Component Paths (optional, supplements auto-discovery)

{
  "skills": "./skills/",
  "agents": "./agents/agent-name.md",
  "hooks": "./hooks/hooks.json",
  "commands": "./commands/command-name.md",
  "mcpServers": "./.mcp.json",
  "lspServers": "./.lsp.json",
  "outputStyles": "./styles/"
}

Path rules:

• All paths relative to plugin root
• Must start with ./
• Custom paths supplement default directories, never replace them

marketplace.json Schema

{
  "$schema": "https://anthropic.com/claude-code/marketplace.schema.json",
  "name": "marketplace-name",
  "description": "Brief marketplace description",
  "owner": {
    "name": "Owner Name",
    "email": "owner@example.com"
  },
  "metadata": {
    "version": "1.0.0",
    "description": "Detailed marketplace description"
  },
  "plugins": [
    {
      "name": "plugin-name",
      "source": "./plugins/plugin-name",
      "description": "Plugin description",
      "version": "1.0.0",
      "author": { "name": "Author" },
      "category": "development",
      "license": "MIT",
      "keywords": ["keyword"],
      "tags": ["community-managed"]
    }
  ]
}

Required fields

• name — kebab-case, no spaces
• owner — object with name (required), email (optional)
• plugins — array of plugin entries, each with name and source

Reserved marketplace names

claude-code-marketplace, claude-code-plugins, claude-plugins-official, anthropic-marketplace, anthropic-plugins, agent-skills, life-sciences. Names impersonating official Anthropic marketplaces are blocked.

Plugin source types

Type	Format
Local path	"./plugins/name"
GitHub	{ "source": "github", "repo": "org/repo", "ref": "main", "sha": "abc" }
Git URL	{ "source": "url", "url": "https://github.com/org/repo.git" }
Git subdir	{ "source": "git-subdir", "url": "org/repo", "path": "plugins/name" }
npm	{ "source": "npm", "package": "name", "version": "^1.0" }

Plugin categories

development, productivity, security, testing, database, deployment, monitoring, design, learning

hooks.json Format

The official format uses nested matcher + hooks[] with type:

{
  "description": "Human-readable description of hooks purpose",
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Write|Edit",
        "hooks": [
          {
            "type": "command",
            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/validate.sh",
            "timeout": 30
          }
        ]
      }
    ],
    "PostToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "command": "python3 ${CLAUDE_PLUGIN_ROOT}/hooks/scripts/check.py",
            "timeout": 10
          }
        ]
      }
    ]
  }
}

Hook types

Type	Field	Description
command	command	Shell command, receives JSON on stdin
http	url	HTTP POST to endpoint
prompt	prompt	Single-turn LLM evaluation
agent	prompt	Agentic verifier with Read/Grep/Glob tools

Hook events

Event	Matcher	Can block?
SessionStart	startup, resume, clear, compact	No
UserPromptSubmit	No	Yes (exit 2)
PreToolUse	Tool name regex	Yes (exit 2)
PostToolUse	Tool name regex	No
Stop	No	Yes (exit 2)
SubagentStart / SubagentStop	Agent type	No / Yes
Notification	Types	No
PreCompact / PostCompact	manual, auto	No

Portability — ${CLAUDE_PLUGIN_ROOT}

Always use ${CLAUDE_PLUGIN_ROOT} for intra-plugin path references. Never hardcode paths.

In hooks.json: "command": "${CLAUDE_PLUGIN_ROOT}/scripts/tool.sh" In MCP config: "args": ["${CLAUDE_PLUGIN_ROOT}/servers/server.js"] In shell scripts: source "${CLAUDE_PLUGIN_ROOT}/lib/common.sh"

Distribution Best Practices

1. Version bumps required — Claude Code caches by version; no bump = no update for users
2. Version in one place — avoid setting version in both plugin.json and marketplace.json (plugin.json wins silently)
3. Pin with sha for reproducible builds in production marketplaces
4. Test locally with claude --plugin-dir ./my-plugin
5. Reload without restart with /reload-plugins
6. Debug loading with claude --debug or /debug

Validation

# Validate marketplace
claude plugin validate .

# Validate individual plugin
claude plugin validate plugins/my-plugin

# Validate from within Claude Code
/plugin validate .

Naming Conventions

Component	Convention	Example
Plugin	kebab-case	code-review-assistant
Skills	kebab-case directories	api-testing/
Commands	kebab-case .md	run-tests.md
Agents	kebab-case .md	code-reviewer.md
Hooks	kebab-case with ext	validate-input.sh
Config	Standard names	hooks.json, .mcp.json

Plugin skills are namespaced as /plugin-name:skill-name to prevent conflicts.