Plugins System

What are Claude Code Plugins?

Plugins are custom collections of development tools that extend Claude Code's capabilities. Think of them as power-ups for your development workflow - you can install everything you need with a single command.

A Plugin can contain four core components:

Slash Commands: Quick shortcuts for common operations
Subagents: Specialized AI agents for specific tasks
MCP Servers: Connections to external tools and data sources
Hooks: Custom behaviors at specific workflow moments

The key innovation: all these components bundle together, so complex development environment setup becomes simple and fast.

Why Use Plugins?

Traditional Tool Management Problems

Without Plugins, development teams face:

🔄 Scattered Tools: Each team member configures their own tools differently
📚 Steep Learning Curve: New members spend days setting up their environment
🔧 Configuration Hell: Everyone maintains their own scripts and configs
🐛 Inconsistent Standards: No unified way to enforce best practices

Plugins Solution

Plugins solve these problems through:

✅ One-Command Installation: Entire toolchain installed instantly
🎯 Standardization: Everyone uses the same tools and workflows
🚀 Rapid Onboarding: New members productive on day one
🔄 Easy Management: Enable/disable plugins as needed

Understanding the Four Components

1. Slash Commands

Slash Commands are entry points for quick operations. They encapsulate complex tasks into simple commands.

Common Patterns:

/test          # Run test suite
/deploy        # Deploy to production
/review        # Start code review process
/docs          # Generate documentation
/build         # Execute optimized build

How They Work:

When you type /test, Claude Code:

Reads the command definition from .claude/commands/test.md
Executes the defined workflow
Returns results to you

Creating Your First Slash Command:

<!-- .claude/commands/hello.md -->
Say hello to the user and show the current project structure.

Now typing /hello will execute this command.

2. Subagents

Subagents are specialized AI agents with deep domain expertise. They're like having expert consultants on your team.

Real-World Examples:

DevOps Agent:

Automates deployment processes
Monitors system health
Handles infrastructure tasks

> Use DevOps agent to set up CI/CD pipeline for this project

Testing Agent:

Generates intelligent test cases
Identifies edge cases
Optimizes test coverage

> Use Testing agent to create comprehensive tests for the authentication module

Security Agent:

Scans code for vulnerabilities
Suggests security improvements
Validates security patterns

> Use Security agent to audit this API endpoint

3. MCP Servers

MCP (Model Context Protocol) Servers provide connectivity to external tools and data sources.

Connection Capabilities:

Development Tools:

- Git: Version control operations
- Docker: Container management
- Kubernetes: Orchestration and deployment

Databases:

- PostgreSQL: Relational data
- MongoDB: Document storage
- Redis: Caching and sessions

Cloud Services:

- AWS: Cloud infrastructure
- Azure: Microsoft cloud
- GCP: Google cloud platform

API Services:

- Internal microservices
- Third-party APIs
- Webhook integrations

Example MCP Server Configuration:

{
  "mcpServers": {
    "database": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-postgres"],
      "env": {
        "POSTGRES_CONNECTION": "postgresql://localhost/mydb"
      }
    }
  }
}

4. Hooks

Hooks customize Claude Code's behavior at specific workflow moments.

Available Hook Types:

Pre-commit Hook:

// .claude/hooks/pre-commit.js
// Runs before code commits
module.exports = async (context) => {
  // Run linters
  // Check formatting
  // Validate tests
  return { allow: true };
};

Post-analysis Hook:

// .claude/hooks/post-analysis.js
// Runs after code analysis
module.exports = async (context) => {
  // Generate reports
  // Update documentation
  // Notify team
};

Error Hook:

// .claude/hooks/error.js
// Runs when errors occur
module.exports = async (error, context) => {
  // Log error details
  // Attempt recovery
  // Notify monitoring systems
};

Installing and Using Plugins

Basic Installation

The simplest way to install a plugin:

/plugin install organization/plugin-name

Example:

/plugin install danavila/devops-toolkit

Claude will:

Download the plugin from the repository
Install all dependencies
Configure all components
Make it immediately available

Managing Plugins

Plugins are designed to be lightweight and toggleable:

# Enable a plugin
/plugin enable plugin-name

# Disable a plugin
/plugin disable plugin-name

# List all installed plugins
/plugin list

# View plugin details
/plugin info plugin-name

# Uninstall a plugin
/plugin uninstall plugin-name

Plugin Lifecycle

Install → Configure → Enable → Use → Disable/Uninstall

Installation: Downloads and sets up the plugin Configuration: Customize plugin settings for your project Enable: Activate plugin features Use: Access slash commands, subagents, and hooks Disable: Temporarily turn off without uninstalling Uninstall: Completely remove the plugin

Plugin Marketplaces

What are Marketplaces?

Marketplaces are repositories where developers share plugins. Anyone can create and host their own marketplace.

Creating a Marketplace

Step 1: Create Configuration File

// .claude-plugin/marketplace.json
{
  "name": "My Marketplace",
  "description": "Custom plugins for our team",
  "plugins": [
    {
      "name": "team-standards",
      "description": "Enforce team coding standards",
      "version": "1.0.0",
      "repository": "github.com/myteam/team-standards"
    }
  ]
}

Step 2: Host on GitHub

git init
git add .claude-plugin/
git commit -m "Initialize plugin marketplace"
git push origin main

Step 3: Share with Team

/plugin marketplace add myteam/plugin-marketplace

Community Marketplaces

Dan Ávila's Marketplace:

/plugin marketplace add danavila/plugins

Contains:

DevOps automation tools
Documentation generators
Project management integrations

Seth Hobson's Repository:

/plugin marketplace add sethhobson/agents

Offers 80+ specialized subagents:

Frontend development (React, Vue, Angular)
Backend development (Node.js, Python, Java)
Data science and machine learning
Mobile development (iOS, Android)

Real-World Plugin Workflows

Scenario 1: Frontend Team Standardization

Problem: Team members use different linting rules and formatting standards

Solution: Create Team Standards Plugin

# Install the team standards plugin
/plugin install company/frontend-standards

Plugin includes:

/lint - Runs ESLint with team config
/format - Applies team Prettier rules
/test - Runs Jest with coverage requirements
React Agent - Enforces component patterns
Accessibility Agent - Ensures WCAG compliance

Result:

Consistent code style across team
Automated quality checks
Reduced code review time

Scenario 2: Full-Stack Productivity Boost

Problem: Repetitive boilerplate code slows development

Solution: Install Productivity Plugin

/plugin install awesome-dev/fullstack-boost

Plugin provides:

/api - Generates REST API with best practices
/component - Creates UI components with tests
/db-migrate - Database migration helper
Backend Agent - API optimization suggestions
Database Agent - Query performance tips

Result:

3x faster feature development
Consistent architecture patterns
Built-in optimization guidance

Scenario 3: Enterprise Security Compliance

Problem: Must meet security standards before deployment

Solution: Security Compliance Plugin

/plugin install enterprise/security-compliance

Plugin enforces:

/security-scan - Automated security checks
/compliance-check - Regulatory compliance validation
/audit-log - Generate audit trail
Security Agent - Vulnerability detection and fixes
Compliance Hook - Pre-commit security validation

Result:

Automated security enforcement
Compliance documentation generated automatically
Reduced security incidents

Creating Your First Plugin

Plugin Structure

my-plugin/
├── .claude-plugin/
│   ├── manifest.json          # Plugin metadata
│   ├── commands/               # Slash commands
│   │   ├── test.md
│   │   └── deploy.md
│   ├── agents/                 # Subagents
│   │   ├── testing-agent.md
│   │   └── deploy-agent.md
│   ├── mcp-servers/            # MCP server configs
│   │   └── custom-tools.json
│   └── hooks/                  # Hooks configuration
│       ├── pre-commit.js
│       └── post-analysis.js
└── README.md

Step 1: Create Manifest

{
  "name": "my-first-plugin",
  "version": "1.0.0",
  "description": "My custom development tools",
  "author": "Your Name",
  "components": {
    "commands": ["test", "deploy"],
    "agents": ["testing-agent"],
    "hooks": ["pre-commit"]
  }
}

Step 2: Add a Slash Command

<!-- .claude-plugin/commands/test.md -->
# Test Command

Run the project test suite with coverage reporting.

## Steps:
1. Check for test files
2. Run Jest with coverage
3. Generate HTML report
4. Open report in browser

Step 3: Create a Subagent

<!-- .claude-plugin/agents/testing-agent.md -->
# Testing Agent

You are a testing expert specializing in comprehensive test coverage.

## Capabilities:
- Generate unit tests for functions and classes
- Create integration tests for APIs
- Design end-to-end test scenarios
- Identify edge cases and test coverage gaps
- Suggest test data and mocking strategies

## Guidelines:
- Follow AAA pattern (Arrange, Act, Assert)
- Aim for 80%+ code coverage
- Include positive and negative test cases
- Mock external dependencies appropriately

Step 4: Add a Hook

// .claude-plugin/hooks/pre-commit.js
module.exports = async (context) => {
  console.log('Running pre-commit checks...');

  // Run linter
  const lintResult = await context.exec('npm run lint');
  if (lintResult.exitCode !== 0) {
    return {
      allow: false,
      message: 'Linting failed. Please fix errors before committing.'
    };
  }

  // Run tests
  const testResult = await context.exec('npm test');
  if (testResult.exitCode !== 0) {
    return {
      allow: false,
      message: 'Tests failed. Please fix failing tests before committing.'
    };
  }

  return { allow: true };
};

Step 5: Test Your Plugin

# Load plugin locally
/plugin install ./my-plugin

# Test slash command
/test

# Use subagent
> Use Testing agent to create tests for UserService

# Verify hook (try to commit)
git add .
git commit -m "test commit"

Best Practices

1. Single Responsibility

Each plugin should focus on one domain:

✅ Good:

- authentication-plugin (handles auth only)
- testing-plugin (handles testing only)
- deployment-plugin (handles deployment only)

❌ Bad:

- everything-plugin (tries to do everything)

2. Composability

Design plugins to work well together:

# Plugins should complement each other
/plugin enable testing-plugin
/plugin enable quality-plugin
/plugin enable deployment-plugin

# They should not conflict

3. Clear Documentation

Every plugin needs:

# Plugin Name

## Description
Clear explanation of what it does

## Installation
Step-by-step installation guide

## Usage
Examples of all commands and features

## Configuration
Available options and settings

## Troubleshooting
Common issues and solutions

4. Version Management

Use semantic versioning:

{
  "version": "1.2.3"
  // 1 = Major (breaking changes)
  // 2 = Minor (new features)
  // 3 = Patch (bug fixes)
}

5. Performance Optimization

Lazy Loading:

// Only load when needed
if (command === '/heavy-operation') {
  const module = await import('./heavy-module');
  module.execute();
}

Caching:

// Cache expensive operations
const cache = new Map();
if (cache.has(key)) {
  return cache.get(key);
}
const result = await expensiveOperation();
cache.set(key, result);

Troubleshooting

Plugin Won't Install

Problem: Plugin installation fails

Solutions:

# Check network connection
ping github.com

# Verify plugin repository exists
git ls-remote https://github.com/org/plugin-name

# Try with verbose logging
/plugin install org/plugin-name --verbose

# Check for conflicting plugins
/plugin list

Slash Command Not Found

Problem: /mycommand says "command not found"

Solutions:

# Verify plugin is enabled
/plugin list

# Enable if disabled
/plugin enable plugin-name

# Reload plugins
/plugin reload

# Check command definition exists
ls .claude-plugin/commands/

Hook Not Triggering

Problem: Pre-commit hook doesn't run

Solutions:

// Check hook is registered
/plugin info plugin-name

// Verify hook file exists and has correct name
ls .claude-plugin/hooks/

// Check hook syntax
node .claude-plugin/hooks/pre-commit.js

// Enable hook debugging
/plugin config plugin-name --debug-hooks

Advanced Topics

Conditional Plugin Loading

// Only load in specific environments
if (process.env.NODE_ENV === 'production') {
  await loadPlugin('production-monitoring');
}

Plugin Dependencies

{
  "name": "advanced-plugin",
  "dependencies": {
    "base-plugin": "^1.0.0",
    "utils-plugin": "^2.1.0"
  }
}

Custom Plugin Configuration

{
  "plugins": {
    "my-plugin": {
      "enabled": true,
      "config": {
        "apiKey": "your-key",
        "timeout": 5000,
        "retries": 3
      }
    }
  }
}

Plugin Security

Best Practices

1. Code Review: Always review plugin code before installation 2. Trusted Sources: Only install from verified marketplaces 3. Permissions: Understand what access plugins request 4. Regular Updates: Keep plugins updated for security patches

Red Flags

⚠️ Warning signs:

Requests excessive permissions
Contains obfuscated code
No source code available
Unknown developer
No documentation

Next Steps

Now that you understand Plugins, you can:

Explore Marketplaces: Browse available plugins

/plugin marketplace add danavila/plugins
/plugin browse

Install Useful Plugins: Start with community favorites
```
/plugin install danavila/devops-toolkit
```

Create Your Plugin: Build tools for your workflow

mkdir my-plugin
cd my-plugin
# Follow the structure above

Share with Community: Publish your plugin

git push origin main
# Share repository URL

Continue reading: Dynamic Memory to learn how Claude Code maintains context across sessions.

What are Claude Code Plugins?​

Why Use Plugins?​

Traditional Tool Management Problems​

Plugins Solution​

Understanding the Four Components​

1. Slash Commands​

2. Subagents​

3. MCP Servers​

4. Hooks​

Installing and Using Plugins​

Basic Installation​

Managing Plugins​

Plugin Lifecycle​

Plugin Marketplaces​

What are Marketplaces?​

Creating a Marketplace​

Community Marketplaces​

Real-World Plugin Workflows​

Scenario 1: Frontend Team Standardization​

Scenario 2: Full-Stack Productivity Boost​

Scenario 3: Enterprise Security Compliance​

Creating Your First Plugin​

Plugin Structure​

Step 1: Create Manifest​

Step 2: Add a Slash Command​

Step 3: Create a Subagent​

Step 4: Add a Hook​

Step 5: Test Your Plugin​

Best Practices​

1. Single Responsibility​

2. Composability​

3. Clear Documentation​

4. Version Management​

5. Performance Optimization​

Troubleshooting​

Plugin Won't Install​

Slash Command Not Found​

Hook Not Triggering​

Advanced Topics​

Conditional Plugin Loading​

Plugin Dependencies​

Custom Plugin Configuration​

Plugin Security​

Best Practices​

Red Flags​

Next Steps​

What are Claude Code Plugins?

Why Use Plugins?

Traditional Tool Management Problems

Plugins Solution

Understanding the Four Components

1. Slash Commands

2. Subagents

3. MCP Servers

4. Hooks

Installing and Using Plugins

Basic Installation

Managing Plugins

Plugin Lifecycle

Plugin Marketplaces

What are Marketplaces?

Creating a Marketplace

Community Marketplaces

Real-World Plugin Workflows

Scenario 1: Frontend Team Standardization

Scenario 2: Full-Stack Productivity Boost

Scenario 3: Enterprise Security Compliance

Creating Your First Plugin

Plugin Structure

Step 1: Create Manifest

Step 2: Add a Slash Command

Step 3: Create a Subagent

Step 4: Add a Hook

Step 5: Test Your Plugin

Best Practices

1. Single Responsibility

2. Composability

3. Clear Documentation

4. Version Management

5. Performance Optimization

Troubleshooting

Plugin Won't Install

Slash Command Not Found

Hook Not Triggering

Advanced Topics

Conditional Plugin Loading

Plugin Dependencies

Custom Plugin Configuration

Plugin Security

Best Practices

Red Flags

Next Steps