MCP (Model Context Protocol) Tutorial - Understanding JSON-RPC for AI Integration

What is Model Context Protocol (MCP)?

Model Context Protocol (MCP) is an open protocol developed by Anthropic that enables AI models like Claude to securely connect with external data sources and tools. Think of it as a standardized way for AI assistants to access your local files, databases, APIs, and other resources in a controlled manner.

Why MCP Matters

✅ Standardized Integration: One protocol for all AI-tool communications
✅ Security First: Controlled access to resources with user permission
✅ Extensible: Easy to build custom MCP servers for your specific needs
✅ JSON-RPC Based: Built on proven, lightweight JSON-RPC 2.0 protocol

MCP and JSON-RPC: The Connection

MCP uses JSON-RPC 2.0 as its underlying communication protocol. This means every interaction between a client (like Claude Desktop) and an MCP server follows JSON-RPC request/response patterns.

Key MCP Methods (JSON-RPC)

initialize

Establish connection and exchange capabilities between client and server

tools/list

Request available tools from the MCP server

tools/call

Execute a specific tool with parameters

resources/list

Get list of available resources (files, data sources, etc.)

resources/read

Read content from a specific resource

Example: MCP Initialize Request

When Claude Desktop connects to an MCP server, it sends an initialize request. Here's what it looks like:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "2024-11-05",
    "capabilities": {
      "roots": {
        "listChanged": true
      },
      "sampling": {}
    },
    "clientInfo": {
      "name": "Claude Desktop",
      "version": "1.0.0"
    }
  }
}

Validate This Request Generate MCP Requests

Server Response

The MCP server responds with its own capabilities:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "protocolVersion": "2024-11-05",
    "capabilities": {
      "tools": {},
      "resources": {
        "subscribe": true,
        "listChanged": true
      }
    },
    "serverInfo": {
      "name": "Example MCP Server",
      "version": "1.0.0"
    }
  }
}

Building Your First MCP Server

Ready to build an MCP server? Here's a simple roadmap:

1
Choose Your Language
Python and TypeScript have official MCP SDKs. Use our Code Generator for templates.
2
Implement Core Methods
At minimum, implement initialize, tools/list, and tools/call methods.
3
Test Your Server
Use our Request Tester to verify your MCP server responds correctly.
4
Connect to Claude Desktop
Configure Claude Desktop to use your MCP server in the settings.

Common MCP Use Cases

📁 File System Access

Give Claude access to read and write local files, perfect for code generation, documentation, and data processing.

🗄️ Database Queries

Connect Claude to databases (PostgreSQL, MongoDB, etc.) to query data, generate reports, and analyze trends.

🌐 API Integration

Integrate third-party APIs (weather, news, CRM systems) to extend Claude's knowledge and capabilities.

⚙️ Custom Tools

Build specialized tools for your workflow: deployment scripts, testing frameworks, monitoring systems.

MCP vs Traditional REST APIs

Feature	MCP (JSON-RPC)	REST API
Protocol	JSON-RPC 2.0	HTTP Methods
Communication	Method-based (RPC calls)	Resource-based (URLs)
Complexity	Simpler for AI integration	More flexible routing
Batch Requests	✅ Native support	❌ Usually requires custom implementation
Use Case	AI model integrations	Web services, public APIs

🔄 Try REST ↔ JSON-RPC Converter

MCP Server Best Practices

✅ DO: Implement Proper Error Handling

Use JSON-RPC error codes (-32700 to -32603 for protocol errors, -32000 to -32099 for application errors).

✅ DO: Validate All Inputs

Use our Validator tool to ensure requests match JSON-RPC 2.0 spec.

✅ DO: Document Your Tools

Provide clear descriptions in tools/list responses so Claude understands when to use each tool.

❌ DON'T: Expose Sensitive Operations

Implement access controls and never expose destructive operations without user confirmation.

❌ DON'T: Ignore Protocol Version

Always check the protocolVersion in initialize requests to ensure compatibility.

🔒 Check Security Best Practices

Learning Resources

🛠️ Tools

JSON-RPC Validator - Validate MCP requests
JSON-RPC Generator - Generate MCP messages
Request Tester - Test your MCP server
Code Generator - Generate MCP server code

📚 Documentation

Ready to Build?

Start building your own MCP server today. Whether you're connecting Claude to your local files, databases, or custom APIs, these tools will help you get started quickly.

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Understanding MCP: Model Context Protocol

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