Claude Code Plugins System - Complete Reference (January 2026)

Plugins extend Claude Code with skills, agents, hooks, MCP servers, and LSP servers. This reference provides complete technical specifications for creating and distributing plugins.

Plugin Components Overview

Plugins can include any combination of:

• Skills: SKILL.md directories that Claude can invoke automatically
• Commands: Markdown files creating

  /name

  shortcuts (legacy; use skills instead)
• Agents: Specialized subagents for specific tasks
• Hooks: Event handlers responding to Claude Code events
• MCP Servers: Model Context Protocol servers for external tool integration
• LSP Servers: Language Server Protocol servers for code intelligence

plugin.json Schema

The

plugin.json

.claude-plugin/

Complete Schema Example

{
  "name": "plugin-name",
  "version": "1.2.0",
  "description": "Brief plugin description",
  "author": {
    "name": "Author Name",
    "email": "author@example.com",
    "url": "https://github.com/author"
  },
  "homepage": "https://docs.example.com/plugin",
  "repository": "https://github.com/author/plugin",
  "license": "MIT",
  "keywords": ["keyword1", "keyword2"],
  "commands": ["./custom/commands/special.md"],
  "agents": "./custom/agents/",
  "skills": "./custom/skills/",
  "hooks": "./config/hooks.json",
  "mcpServers": "./mcp-config.json",
  "outputStyles": "./styles/",
  "lspServers": "./.lsp.json"
}

Required Fields

name

"deployment-tools"

Metadata Fields

version

"2.1.0"

description

"Deployment automation tools"

author

{"name": "Dev Team", "email": "dev@company.com"}

homepage

"https://docs.example.com"

repository

"https://github.com/user/plugin"

license

"MIT"

"Apache-2.0"

keywords

["deployment", "ci-cd"]

Component Path Fields

commands

"./custom/cmd.md"

["./cmd1.md"]

agents

["./agents/reviewer.md"]

skills

"./custom/skills/"

hooks

"./hooks.json"

mcpServers

"./mcp-config.json"

outputStyles

"./styles/"

lspServers

"./.lsp.json"

Path behavior rules:

• Custom paths supplement default directories - they don't replace them
• If

  commands/

  exists, it's loaded in addition to custom command paths
• All paths must be relative to plugin root and start with

  ./

• Multiple paths can be specified as arrays
• CRITICAL:

  agents

  field must ALWAYS be an array of individual file paths, never a directory string

Common validation errors:

// CORRECT agents field
"agents": ["./agents/security-reviewer.md", "./agents/code-formatter.md"]

// INCORRECT - will fail validation
"agents": "./agents/"
"agents": "./custom/agents/"

Plugin Directory Structure

Standard Layout

enterprise-plugin/
├── .claude-plugin/           # Metadata directory
│   └── plugin.json          # Required: plugin manifest
├── commands/                 # Default command location
│   ├── status.md
│   └── logs.md
├── agents/                   # Default agent location
│   ├── security-reviewer.md
│   ├── performance-tester.md
│   └── compliance-checker.md
├── skills/                   # Agent Skills
│   ├── code-reviewer/
│   │   └── SKILL.md
│   └── pdf-processor/
│       ├── SKILL.md
│       └── scripts/
├── hooks/                    # Hook configurations
│   ├── hooks.json           # Main hook config
│   └── security-hooks.json  # Additional hooks
├── .mcp.json                # MCP server definitions
├── .lsp.json                # LSP server configurations
├── scripts/                 # Hook and utility scripts
│   ├── security-scan.sh
│   ├── format-code.py
│   └── deploy.js
├── LICENSE                  # License file
└── CHANGELOG.md             # Version history

Critical: The

.claude-plugin/

plugin.json

.claude-plugin/

File Locations Reference

.claude-plugin/plugin.json

commands/

agents/

skills/

<name>/SKILL.md

hooks/hooks.json

.mcp.json

.lsp.json

Plugin Components Reference

Skills

Plugins add skills to Claude Code, creating

/name

Location:

skills/

commands/

Skill structure:

skills/
├── pdf-processor/
│   ├── SKILL.md
│   ├── reference.md (optional)
│   └── scripts/ (optional)
└── code-reviewer/
    └── SKILL.md

Integration behavior:

• Skills and commands are automatically discovered when the plugin is installed
• Claude can invoke them automatically based on task context
• Skills can include supporting files alongside SKILL.md

Agents

Plugins can provide specialized subagents for specific tasks that Claude can invoke automatically when appropriate.

Location:

agents/

File format: Markdown files with YAML frontmatter describing agent capabilities

Integration points:

• Agents appear in the

  /agents

  interface
• Claude can invoke agents automatically based on task context
• Agents can be invoked manually by users
• Plugin agents work alongside built-in Claude agents

Hooks

Plugins can provide event handlers that respond to Claude Code events automatically.

Location:

hooks/hooks.json

Format: JSON configuration with event matchers and actions

Hook configuration:

{
  "hooks": {
    "PostToolUse": [
      {
        "matcher": "Write|Edit",
        "hooks": [
          {
            "type": "command",
            "command": "${CLAUDE_PLUGIN_ROOT}/scripts/format-code.sh"
          }
        ]
      }
    ]
  }
}

Available events:

• PreToolUse

  : Before Claude uses any tool

• PostToolUse

  : After Claude successfully uses any tool

• PostToolUseFailure

  : After Claude tool execution fails

• PermissionRequest

  : When a permission dialog is shown

• UserPromptSubmit

  : When user submits a prompt

• Notification

  : When Claude Code sends notifications

• Stop

  : When Claude attempts to stop

• SubagentStart

  : When a subagent is started

• SubagentStop

  : When a subagent attempts to stop

• Setup

  : When

  --init

  ,

  --init-only

  , or

  --maintenance

  flags are used

• SessionStart

  : At the beginning of sessions

• SessionEnd

  : At the end of sessions

• PreCompact

  : Before conversation history is compacted

For complete hook reference and examples, see Claude Hooks Reference

Hook types:

• command

  : Execute shell commands or scripts

• prompt

  : Evaluate a prompt with an LLM (uses

  $ARGUMENTS

  placeholder for context)

• agent

  : Run an agentic verifier with tools for complex verification tasks

MCP Servers

Plugins can bundle Model Context Protocol (MCP) servers to connect Claude Code with external tools and services.

Location:

.mcp.json

Format: Standard MCP server configuration

MCP server configuration:

{
  "mcpServers": {
    "plugin-database": {
      "command": "${CLAUDE_PLUGIN_ROOT}/servers/db-server",
      "args": ["--config", "${CLAUDE_PLUGIN_ROOT}/config.json"],
      "env": {
        "DB_PATH": "${CLAUDE_PLUGIN_ROOT}/data"
      }
    },
    "plugin-api-client": {
      "command": "npx",
      "args": ["@company/mcp-server", "--plugin-mode"],
      "cwd": "${CLAUDE_PLUGIN_ROOT}"
    }
  }
}

Integration behavior:

• Plugin MCP servers start automatically when the plugin is enabled
• Servers appear as standard MCP tools in Claude's toolkit
• Server capabilities integrate seamlessly with Claude's existing tools
• Plugin servers can be configured independently of user MCP servers

LSP Servers

Plugins can provide Language Server Protocol (LSP) servers to give Claude real-time code intelligence while working on your codebase.

LSP integration provides:

• Instant diagnostics: Claude sees errors and warnings immediately after each edit
• Code navigation: go to definition, find references, and hover information
• Language awareness: type information and documentation for code symbols

Location:

.lsp.json

plugin.json

Format: JSON configuration mapping language server names to their configurations

.lsp.json

{
  "go": {
    "command": "gopls",
    "args": ["serve"],
    "extensionToLanguage": {
      ".go": "go"
    }
  }
}

Inline in

plugin.json

{
  "name": "my-plugin",
  "lspServers": {
    "go": {
      "command": "gopls",
      "args": ["serve"],
      "extensionToLanguage": {
        ".go": "go"
      }
    }
  }
}

Required fields:

command

extensionToLanguage

Optional fields:

args

transport

stdio

socket

env

initializationOptions

settings

workspace/didChangeConfiguration

workspaceFolder

startupTimeout

shutdownTimeout

restartOnCrash

maxRestarts

Important: You must install the language server binary separately. LSP plugins configure how Claude Code connects to a language server, but they don't include the server itself.

Available LSP plugins:

pyright-lsp

pip install pyright

npm install -g pyright

typescript-lsp

npm install -g typescript-language-server typescript

rust-lsp

Plugin Caching and File Resolution

For security and verification purposes, Claude Code copies plugins to a cache directory rather than using them in-place. Understanding this behavior is important when developing plugins that reference external files.

How Plugin Caching Works

When you install a plugin, Claude Code copies the plugin files to a cache directory:

• For marketplace plugins with relative paths: The path specified in the

  source

  field is copied recursively. For example, if your marketplace entry specifies

  "source": "./plugins/my-plugin"

  , the entire

  ./plugins

  directory is copied.
• For plugins with

  .claude-plugin/plugin.json

  : The implicit root directory (the directory containing

  .claude-plugin/plugin.json

  ) is copied recursively.

Path Traversal Limitations

Plugins cannot reference files outside their copied directory structure. Paths that traverse outside the plugin root (such as

../shared-utils

Working with External Dependencies

If your plugin needs to access files outside its directory, you have two options:

Option 1: Use symlinks

Create symbolic links to external files within your plugin directory. Symlinks are honored during the copy process:

# Inside your plugin directory
ln -s /path/to/shared-utils ./shared-utils

The symlinked content will be copied into the plugin cache.

Option 2: Restructure your marketplace

Set the plugin path to a parent directory that contains all required files, then provide the rest of the plugin manifest directly in the marketplace entry:

{
  "name": "my-plugin",
  "source": "./",
  "description": "Plugin that needs root-level access",
  "commands": ["./plugins/my-plugin/commands/"],
  "agents": ["./plugins/my-plugin/agents/"],
  "strict": false
}

This approach copies the entire marketplace root, giving your plugin access to sibling directories.

Note: Symlinks that point to locations outside the plugin's logical root are followed during copying. This provides flexibility while maintaining the security benefits of the caching system.

Plugin Installation Scopes

When you install a plugin, you choose a scope that determines where the plugin is available and who else can use it:

user

~/.claude/settings.json

project

.claude/settings.json

local

.claude/settings.local.json

managed

managed-settings.json

Environment Variables

${CLAUDE_PLUGIN_ROOT}

{
  "hooks": {
    "PostToolUse": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "${CLAUDE_PLUGIN_ROOT}/scripts/process.sh"
          }
        ]
      }
    ]
  }
}

${CLAUDE_PROJECT_DIR}

Plugin Marketplaces

Marketplace Schema

Create

.claude-plugin/marketplace.json

{
  "name": "company-tools",
  "owner": {
    "name": "DevTools Team",
    "email": "devtools@example.com"
  },
  "plugins": [
    {
      "name": "code-formatter",
      "source": "./plugins/formatter",
      "description": "Automatic code formatting on save",
      "version": "2.1.0",
      "author": {
        "name": "DevTools Team"
      }
    },
    {
      "name": "deployment-tools",
      "source": {
        "source": "github",
        "repo": "company/deploy-plugin"
      },
      "description": "Deployment automation tools"
    }
  ]
}

Required Marketplace Fields

name

"acme-tools"

owner

plugins

Reserved names:

claude-code-marketplace

claude-code-plugins

claude-plugins-official

anthropic-marketplace

anthropic-plugins

agent-skills

life-sciences

Plugin Sources

Relative paths

For plugins in the same repository:

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

Note: Relative paths only work when users add your marketplace via Git (GitHub, GitLab, or git URL). If users add your marketplace via a direct URL to the

marketplace.json

GitHub repositories

{
  "name": "github-plugin",
  "source": {
    "source": "github",
    "repo": "owner/plugin-repo"
  }
}

You can pin to a specific branch, tag, or commit:

{
  "name": "github-plugin",
  "source": {
    "source": "github",
    "repo": "owner/plugin-repo",
    "ref": "v2.0.0",
    "sha": "a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0"
  }
}

repo

owner/repo

ref

sha

Git repositories

{
  "name": "git-plugin",
  "source": {
    "source": "url",
    "url": "https://gitlab.com/team/plugin.git"
  }
}

You can pin to a specific branch, tag, or commit:

{
  "name": "git-plugin",
  "source": {
    "source": "url",
    "url": "https://gitlab.com/team/plugin.git",
    "ref": "main",
    "sha": "a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0"
  }
}

url

.git

ref

sha

CLI Commands Reference

Claude Code provides CLI commands for non-interactive plugin management, useful for scripting and automation.

plugin install

Install a plugin from available marketplaces.

claude plugin install <plugin> [options]

Arguments:

• <plugin>

  : Plugin name or

  plugin-name@marketplace-name

  for a specific marketplace

Options:

-s, --scope <scope>

user

project

local

user

-h, --help

Examples:

# Install to user scope (default)
claude plugin install formatter@my-marketplace

# Install to project scope (shared with team)
claude plugin install formatter@my-marketplace --scope project

# Install to local scope (gitignored)
claude plugin install formatter@my-marketplace --scope local

plugin uninstall

Remove an installed plugin.

claude plugin uninstall <plugin> [options]

Arguments:

• <plugin>

  : Plugin name or

  plugin-name@marketplace-name

Options:

-s, --scope <scope>

user

project

local

user

-h, --help

Aliases:

remove

rm

plugin enable

Enable a disabled plugin.

claude plugin enable <plugin> [options]

Arguments:

• <plugin>

  : Plugin name or

  plugin-name@marketplace-name

Options:

-s, --scope <scope>

user

project

local

user

-h, --help

plugin disable

Disable a plugin without uninstalling it.

claude plugin disable <plugin> [options]

Arguments:

• <plugin>

  : Plugin name or

  plugin-name@marketplace-name

Options:

-s, --scope <scope>

user

project

local

user

-h, --help

plugin update

Update a plugin to the latest version.

claude plugin update <plugin> [options]

Arguments:

• <plugin>

  : Plugin name or

  plugin-name@marketplace-name

Options:

-s, --scope <scope>

user

project

local

managed

user

-h, --help

Debugging and Development Tools

Debugging Commands

Use

claude --debug

claude --debug

This shows:

• Which plugins are being loaded
• Any errors in plugin manifests
• Command, agent, and hook registration
• MCP server initialization

Common Issues

plugin.json

claude plugin validate

/plugin validate

agents: Invalid input

"agents": "./agents/"

"agents": ["./agents/file.md"]

commands/

.claude-plugin/

chmod +x script.sh

${CLAUDE_PLUGIN_ROOT}

./

Executable not found in $PATH

npm install -g typescript-language-server

Validation Commands

# CLI (from terminal)
claude plugin validate .
claude plugin validate ./path/to/plugin

# In Claude Code session
/plugin validate .
/plugin validate ./path/to/plugin

Testing Without Installation

# Load plugin for current session only
claude --plugin-dir ./my-plugin

# Load multiple plugins
claude --plugin-dir ./plugin-one --plugin-dir ./plugin-two

Enterprise Features

Required Marketplaces for Teams

Configure your repository so team members are automatically prompted to install your marketplace when they trust the project folder. Add your marketplace to

.claude/settings.json

{
  "extraKnownMarketplaces": {
    "company-tools": {
      "source": {
        "source": "github",
        "repo": "your-org/claude-plugins"
      }
    }
  }
}

You can also specify which plugins should be enabled by default:

{
  "enabledPlugins": {
    "code-formatter@company-tools": true,
    "deployment-tools@company-tools": true
  }
}

Managed Marketplace Restrictions

For organizations requiring strict control over plugin sources, administrators can restrict which plugin marketplaces users are allowed to add using the

strictKnownMarketplaces

When

strictKnownMarketplaces

[]

Common configurations:

Disable all marketplace additions:

{
  "strictKnownMarketplaces": []
}

Allow specific marketplaces only:

{
  "strictKnownMarketplaces": [
    {
      "source": "github",
      "repo": "acme-corp/approved-plugins"
    },
    {
      "source": "github",
      "repo": "acme-corp/security-tools",
      "ref": "v2.0"
    },
    {
      "source": "url",
      "url": "https://plugins.example.com/marketplace.json"
    }
  ]
}

Allow all marketplaces from an internal git server using regex pattern matching:

{
  "strictKnownMarketplaces": [
    {
      "source": "hostPattern",
      "hostPattern": "^github\\.example\\.com$"
    }
  ]
}

How restrictions work:

Restrictions are validated early in the plugin installation process, before any network requests or filesystem operations occur. This prevents unauthorized marketplace access attempts.

The allowlist uses exact matching for most source types. For a marketplace to be allowed, all specified fields must match exactly:

• For GitHub sources:

  repo

  is required, and

  ref

  or

  path

  must also match if specified in the allowlist
• For URL sources: the full URL must match exactly
• For

  hostPattern

  sources: the marketplace host is matched against the regex pattern

Because

strictKnownMarketplaces

Private Repository Authentication

GITHUB_TOKEN

GH_TOKEN

GITLAB_TOKEN

GL_TOKEN

BITBUCKET_TOKEN

Set the token in your shell configuration (e.g.,

.bashrc

.zshrc

export GITHUB_TOKEN=ghp_xxxxxxxxxxxxxxxxxxxx

For manual installation and updates: Claude Code uses your existing git credential helpers. If

git clone

For background auto-updates: Set the appropriate authentication token in your environment. GitHub Actions automatically provides

GITHUB_TOKEN

Distribution and Versioning

Version Management

Follow semantic versioning for plugin releases:

{
  "name": "my-plugin",
  "version": "2.1.0"
}

Version format:

MAJOR.MINOR.PATCH

• MAJOR: Breaking changes (incompatible API changes)
• MINOR: New features (backward-compatible additions)
• PATCH: Bug fixes (backward-compatible fixes)

Best practices:

• Start at

  1.0.0

  for your first stable release
• Update the version in

  plugin.json

  before distributing changes
• Document changes in a

  CHANGELOG.md

  file
• Use pre-release versions like

  2.0.0-beta.1

  for testing

Constraints and Limitations

• Plugins copied to cache, not used in-place
• Cannot reference files outside plugin directory (

  ../

  fails)
• LSP servers require separate binary installation
• All paths must be relative, start with

  ./

• Path traversal (

  ..

  ) not allowed
• Scripts must be executable (

  chmod +x

  )
• Reserved marketplace names:

  claude-code-marketplace

  ,

  anthropic-plugins

  ,

  agent-skills

Sources

• Plugins Reference (accessed 2026-01-28)
• Create Plugins (accessed 2026-01-28)
• Plugin Marketplaces (accessed 2026-01-28)
• Skills Reference
• Hooks Reference
• MCP Reference