21st.dev Magic + Claude Desktop App: Complete MCP Integration

21st.dev Magic is a MCP server that Create crafted UI components inspired by the best 21st.dev design engineers..

When integrated with Claude Desktop App, you can:

• Generate crafted UI components using AI design patterns
• Live preview of generated components
• Full TypeScript support for generated components

This guide provides step-by-step instructions to set up 21st.dev Magic in Claude Desktop App, including configuration, examples, and troubleshooting.

What You'll Achieve

After completing this setup:

• 21st.dev Magic will be fully integrated and operational
• You can use 21st.dev Magic tools directly in Claude Desktop App
• All 21st.dev Magic capabilities will be available for your workflows
• Access to 4 different tools

Prerequisites

Before starting, ensure you have:

• 21st.dev account
• API key
• 21st.dev Magic API key for authentication
• Claude Desktop App installed and configured
• Compatible operating system (Windows, macOS, Linux)

Installation

Step 1: Install 21st.dev Magic

Manual installation steps:

1. Generate API key from 21st.dev Magic Console
2. Add configuration to IDE-specific JSON config
3. Restart IDE to load MCP server

Configuration

Step 2: Configure Claude Desktop App

1. Locate your configuration file:

   • Windows: %APPDATA%\\Claude\\claude_desktop_config.json
   • macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
   • Linux: ~/.config/Claude/claude_desktop_config.json

2. Add server configuration:

{
  "mcpServers": {
    "21stdev-magic": {
      "command": "21st.dev magic",
      "args": [""],
      "env": {
        "API_KEY": "your-21st-dev-api-key"
      }
    }
  }
}

3. Restart Claude Desktop App

Completely quit and restart Claude Desktop App to load the new configuration.

Examples

Once configured, you can use 21st.dev Magic in Claude Desktop App:

Create Navigation Bar

Generate a modern responsive navigation component

Ask Claude Desktop App: "/ui create a modern navigation bar with responsive design"

Expected Result: Responsive navigation component with mobile menu, logo placement, and styling

Generate Dashboard Card

Create a dashboard card with metrics display

Ask Claude Desktop App: "/ui design a dashboard card showing user analytics with charts"

Expected Result: Card component with chart integration, metrics display, and responsive layout

Build Form Component

Create a contact form with validation

Ask Claude Desktop App: "/ui create a contact form with validation and modern styling"

Expected Result: Form component with input validation, error states, and submit handling

Design Landing Hero

Generate a landing page hero section

Ask Claude Desktop App: "/ui build a hero section for a SaaS product with CTA buttons"

Expected Result: Hero component with headline, description, call-to-action buttons, and background

Testing Your Setup

1. Start a new conversation in Claude Desktop App
2. Ask Claude Desktop App to list available tools
3. Try using 21st.dev Magic functionality

Test prompts:

• "Can you list the available tools from 21st.dev Magic?"
• "Please use 21st.dev Magic to {example_task}"

Troubleshooting

Common Issues

API Key Invalid

Symptoms: Authentication errors, Access denied messages, Server connection failures

Cause: Invalid or expired API key

Solution:

• Generate new API key from 21st.dev Magic Console
• Update API_KEY in IDE configuration
• Restart IDE to reload configuration

IDE Not Detecting MCP Server

Symptoms: MCP commands not available, Server not listed in IDE

Cause: Incorrect configuration file or location

Solution:

• Verify config file is in correct location for your IDE
• Check JSON syntax in configuration file
• Restart IDE after configuration changes
• Use CLI installation for automatic setup

Component Generation Fails

Symptoms: Empty responses, Error messages during generation

Cause: Network issues or service limitations

Solution:

• Check internet connectivity
• Verify API key has sufficient quota
• Try simpler prompts initially
• Contact support if issues persist

TypeScript Errors in Generated Code

Symptoms: Type errors, Compilation failures

Cause: Missing dependencies or type definitions

Solution:

• Install required TypeScript dependencies
• Update @types packages
• Configure TypeScript strict mode properly
• Import necessary type definitions

Server Not Appearing

Symptoms: No server in interface, Tools not available

Cause: Configuration file error or server installation issue

Solution:

• Validate JSON syntax using online validator
• Check configuration file location
• Verify server installation
• Restart Claude Desktop completely

Server Error on Startup

Symptoms: Error messages in logs, Server fails to start

Cause: Missing dependencies or environment variables

Solution:

• Check server requirements are met
• Verify environment variables are set
• Check system logs for detailed errors

21st.dev Magic not appearing in Claude Desktop App

Symptoms: Server not listed, Tools not available

Cause: Configuration or installation issue

Solution:

• Verify configuration syntax
• Check 21st.dev Magic installation
• Restart Claude Desktop App
• Check logs for error messages

Next Steps

Now that 21st.dev Magic is integrated with Claude Desktop App:

• Explore all 21st.dev Magic capabilities through Claude Desktop App
• Check out other MCP servers that work with Claude Desktop App
• Join the MCP community for tips and support
• Consider contributing to 21st.dev Magic development

Need Help?

• Search for 21st.dev Magic documentation
• Check the Claude Desktop App MCP guide
• Join the MCP community discussions