MCP Servers

Extend Claude Code capabilities with Model Context Protocol to connect external tools and services

MCP Servers

MCP (Model Context Protocol) is an open standard by Anthropic that allows Claude Code to connect to external tools, databases, APIs, and services. With MCP, you can significantly extend Claude Code's capabilities.

What is MCP?

Core Concepts

MCP is an open protocol that defines communication standards between AI assistants and external systems. It consists of three core components:

Component Description Examples
Tools Executable actions Query databases, send requests, manipulate files
Resources Readable data File contents, API responses, database records
Prompts Predefined task templates Code review templates, report generation templates

Why MCP?

  • Extended capabilities: Let Claude access systems it couldn't otherwise reach
  • Real-time data: Get the latest documentation, database content, API data
  • Automation: Execute deployments, send notifications, manage resources
  • Privacy: Data processed locally, no need to upload to the cloud

Quick Start

Check MCP Status

> /mcp

Shows the status of currently configured MCP servers.

Add MCP Server

Use the claude mcp add command:

# Add filesystem server
claude mcp add filesystem npx -y @modelcontextprotocol/server-filesystem /path/to/directory

# Add SQLite database server
claude mcp add sqlite npx -y mcp-server-sqlite ./database.db

# Add custom server
claude mcp add my-server node /path/to/server.js

Configuration File

You can also create a .mcp.json file in your project root:

{
  "filesystem": {
    "command": "npx",
    "args": ["-y", "@modelcontextprotocol/server-filesystem", "/allowed/path"]
  },
  "database": {
    "command": "npx",
    "args": ["-y", "mcp-server-sqlite", "./data.db"]
  }
}

Filesystem

Access local filesystem:

{
  "filesystem": {
    "command": "npx",
    "args": ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/directory"]
  }
}

Features: Read, write, and search files in the specified directory.

SQLite Database

Connect to SQLite database:

{
  "sqlite": {
    "command": "npx",
    "args": ["-y", "mcp-server-sqlite", "./database.db"]
  }
}

Features: Execute SQL queries, manage database schema.

GitHub

Connect to GitHub repositories:

{
  "github": {
    "command": "npx",
    "args": ["-y", "@modelcontextprotocol/server-github"],
    "env": {
      "GITHUB_TOKEN": "${GITHUB_TOKEN}"
    }
  }
}

Features: Manage Issues, PRs, repository operations.

Context7 (Documentation Retrieval)

Get the latest library documentation:

{
  "context7": {
    "command": "npx",
    "args": ["-y", "@context7/mcp-server"]
  }
}

Features: Retrieve up-to-date documentation and code examples for any library.

Supabase

Connect to Supabase backend:

{
  "supabase": {
    "command": "npx",
    "args": ["-y", "@supabase/mcp-server"],
    "env": {
      "SUPABASE_URL": "${SUPABASE_URL}",
      "SUPABASE_KEY": "${SUPABASE_KEY}"
    }
  }
}

Features: Database operations, authentication, storage management.

Docker

Container management:

{
  "docker": {
    "command": "npx",
    "args": ["-y", "@docker/mcp-server"]
  }
}

Features: Manage containers, images, networks.

Server Types

stdio (Local Process)

The most common type, runs as a local subprocess:

{
  "my-server": {
    "command": "node",
    "args": ["./server.js"],
    "env": {
      "API_KEY": "${API_KEY}"
    }
  }
}

Characteristics: - Runs locally, data stays on your machine - Claude Code manages process lifecycle - Ideal for filesystem, local databases

SSE (Server-Sent Events)

Connect to remote hosted MCP servers:

{
  "remote-server": {
    "type": "sse",
    "url": "https://mcp.example.com/sse"
  }
}

Characteristics: - Suitable for cloud services - Supports OAuth authentication - No local installation required

HTTP

RESTful API approach:

{
  "api-server": {
    "type": "http",
    "url": "https://api.example.com/mcp",
    "headers": {
      "Authorization": "Bearer ${API_TOKEN}"
    }
  }
}

Environment Variables

MCP configuration supports environment variable substitution:

{
  "my-server": {
    "command": "node",
    "args": ["${CLAUDE_PLUGIN_ROOT}/server.js"],
    "env": {
      "DATABASE_URL": "${DATABASE_URL}",
      "API_KEY": "${API_KEY}",
      "DEFAULT_NAMESPACE": "${K8S_NAMESPACE:-default}"
    }
  }
}

Syntax: - ${VAR} - Substitute with environment variable value - ${VAR:-default} - Use default value if variable is not set

Practical Examples

Example 1: Database Query Assistant

{
  "postgres": {
    "command": "npx",
    "args": ["-y", "mcp-server-postgres"],
    "env": {
      "DATABASE_URL": "postgresql://user:pass@localhost/mydb"
    }
  }
}

Usage:

> Query total order amount for the last 7 days
> Find the top 10 users with the most purchases

Example 2: Kubernetes Operations

{
  "kubernetes": {
    "command": "node",
    "args": ["./k8s-mcp-server.js"],
    "env": {
      "KUBECONFIG": "${KUBECONFIG}",
      "K8S_NAMESPACE": "${K8S_NAMESPACE:-default}"
    }
  }
}

Usage:

> List the status of all Pods
> Restart the api-server deployment
> Show recent error logs

Example 3: Multi-Server Configuration

{
  "filesystem": {
    "command": "npx",
    "args": ["-y", "@modelcontextprotocol/server-filesystem", "./src"]
  },
  "database": {
    "command": "npx",
    "args": ["-y", "mcp-server-sqlite", "./data.db"]
  },
  "github": {
    "command": "npx",
    "args": ["-y", "@modelcontextprotocol/server-github"],
    "env": {
      "GITHUB_TOKEN": "${GITHUB_TOKEN}"
    }
  }
}

Troubleshooting

Server Won't Start

  1. Check if the command is properly installed: bash npx -y @modelcontextprotocol/server-filesystem --help

  2. Check if environment variables are set: bash echo $GITHUB_TOKEN

  3. Check Claude Code logs for error messages

Tools Not Available

  1. Use /mcp to check server status
  2. Verify configuration file format (JSON syntax)
  3. Restart Claude Code to reload configuration

Permission Issues

  • Ensure file paths have read/write permissions
  • Database connection string is correct
  • API Token is valid and has sufficient permissions

Security Recommendations

  1. Principle of least privilege: Only grant necessary access
  2. Protect sensitive info: Use environment variables for tokens and passwords
  3. Limit path access: Only expose necessary directories for filesystem servers
  4. Rotate keys regularly: Periodically update API tokens

Next Steps

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