MCP Marketplace

What's an MCP Server?

MCP servers are specialized extensions that enhance Cline's capabilities. They enable Cline to perform additional tasks like fetching web pages, processing images, accessing APIs, and much more.

MCP Marketplace Walkthrough

The MCP Marketplace provides a one-click installation experience for hundreds of MCP servers across various categories.

1. Access the Marketplace

• In Cline, click the "Extensions" button (square icon) in the top toolbar

• The MCP marketplace will open, showing available servers by category

2. Browse and Select a Server

• Browse servers by category (Search, File-systems, Browser-automation, Research-data, etc.)

• Click on a server to see details about its capabilities and requirements

3. Install and Configure

• Click the install button for your chosen server

• If the server requires an API key (most do), Cline will guide you through:

  • Where to get the API key

  • How to enter it securely

• The server will be added to your MCP settings automatically

4. Verify Installation

• Cline will show confirmation when installation is complete

• Check the server status in Cline's MCP settings UI

5. Using Your New Server

• After successful installation, Cline will automatically integrate the server's capabilities

• You'll see new tools and resources available in Cline's system prompt

• Simply ask Cline to use the capabilities of your new server

• Example: "Search the web for recent React updates using Perplexity"

Corporate Users: If you're using Cline in a corporate environment, ensure you have permission to install third-party MCP servers according to your organization's security policies.

What Happens Behind the Scenes

When you install an MCP server, several things happen automatically:

1. Installation Process

• The server code is cloned/installed to /Users/<username>/Documents/Cline/MCP/

• Dependencies are installed

• The server is built (TypeScript/JavaScript compilation or Python package installation)

2. Configuration

• The MCP settings file is updated with your server configuration

• This file is located at: /Users/<username>/Library/Application Support/Code/User/globalStorage/saoudrizwan.claude-dev/settings/cline_mcp_settings.json

• Environment variables (like API keys) are securely stored

• The server path is registered

3. Server Launch

• Cline detects the configuration change

• Cline launches your server as a separate process

• Communication is established via stdio or HTTP

4. Integration with Cline

• Your server's capabilities are added to Cline's system prompt

• Tools become available via use_mcp_tool commands

• Resources become available via access_mcp_resource commands

• Cline can now use these capabilities when prompted by the user

Troubleshooting

System Requirements

Make sure your system meets these requirements:

• Node.js 18.x or newer

  • Check by running: node --version

  • Install from: https://nodejs.org/

  • Required for JavaScript/TypeScript implementations

• Python 3.10 or newer

  • Check by running: python --version

  • Install from: https://python.org/

  • Note: Some specialized implementations may require Python 3.11+

• UV Package Manager

  • Modern Python package manager for dependency isolation

  • Install using:

    curl -LsSf https://astral.sh/uv/install.sh | sh

    Or: pip install uv

  • Verify with: uv --version

If any of these commands fail or show older versions, please install/update before continuing!

Common Installation Issues

• Ensure your internet connection is stable

• Check that you have the necessary permissions to install new software

• Verify that the API key was entered correctly (if required)

• Check the server status in the MCP settings UI for any error messages

How to Remove an MCP Server

To completely remove a faulty MCP server:

1. Open the MCP settings file: /Users/<username>/Library/Application Support/Code/User/globalStorage/saoudrizwan.claude-dev/settings/cline_mcp_settings.json

2. Delete the entire entry for your server from the mcpServers object

3. Save the file

4. Restart Cline

I'm Still Getting an Error

If you're getting an error when using an MCP server, you can try the following:

• Check the MCP settings file for errors

• Use a Claude Sonnet model for installation

• Verify that paths to your server's files are correct

• Ensure all required environment variables are set

• Check if another process is using the same port (for HTTP-based servers)

• Try removing and reinstalling the server (remove from both the cline_mcp_settings.json file and the /Users/<username>/Documents/Cline/MCP/ directory)

• Use a terminal and run the command with its arguments directly. This will allow you to see the same errors that Cline is seeing

MCP Server Rules

Cline is already aware of your active MCP servers and what they are for, but when you have a lot of MCP servers enabled, it can be useful to define when to use each server.

Utilize a .clinerules file or custom instructions to support intelligent MCP server activation through keyword-based triggers, making Cline's tool selection more intuitive and context-aware.

How MCP Rules Work

MCP Rules group your connected MCP servers into functional categories and define trigger keywords that activate them automatically when detected in your conversations with Cline.

{
  "mcpRules": {
    "webInteraction": {
      "servers": [
        "firecrawl-mcp-server",
        "fetch-mcp"
      ],
      "triggers": [
        "web", "scrape", "browse", "website"
      ],
      "description": "Tools for web browsing and scraping"
    }
  }
}

Configuration Structure

1. Categories: Group related servers (e.g., "webInteraction", "mediaAndDesign")

2. Servers: List server names in each category

3. Triggers: Keywords that activate these servers

4. Description: Human-readable category explanation

Benefits of MCP Rules

• Contextual Tool Selection: Cline selects appropriate tools based on conversation context

• Reduced Friction: No need to manually specify which tool to use

• Organized Capabilities: Logically group related tools and servers

• Prioritization: Handle ambiguous cases with explicit priority ordering

Example Usage

When you write "Can you scrape this website?", Cline detects "scrape" and "website" as triggers, automatically selecting web-related MCP servers.

For finance tasks like "What's Apple's stock price?", keywords like "stock" and "price" trigger finance-related servers.

Quick Start Template

{
  "mcpRules": {
    "category1": {
      "servers": [
        "server-name-1",
        "server-name-2"
      ],
      "triggers": [
        "keyword1", "keyword2", "phrase1", "phrase2"
      ],
      "description": "Description of what these tools do"
    },
    "category2": {
      "servers": [
        "server-name-3"
      ],
      "triggers": [
        "keyword3", "keyword4", "phrase3"
      ],
      "description": "Description of what these tools do"
    },
    "category3": {
      "servers": [
        "server-name-4",
        "server-name-5"
      ],
      "triggers": [
        "keyword5", "keyword6", "phrase4"
      ],
      "description": "Description of what these tools do"
    }
  },
  "defaultBehavior": {
    "priorityOrder": [
      "category1",
      "category2",
      "category3"
    ],
    "fallbackBehavior": "Ask user which tool would be most appropriate"
  }
}

Add this to your .clinerules file or to your custom instructions to make Cline's MCP server selection more intuitive and context-aware.