MCP Server with LangGraph Agent

Read Complete Medium Article here : Building an AI Agent with Model Context Protocol (MCP): A Complete Guide

📖 Overview

This project demonstrates a complete implementation of the Model Context Protocol (MCP) with an intelligent agent built using LangGraph and OpenAI. The system enables AI applications to seamlessly interact with external tools through a standardized protocol.

🧩 What is MCP (Model Context Protocol)?

Model Context Protocol (MCP) is an open protocol that standardizes how applications provide context to Large Language Models (LLMs). Think of it as a universal adapter that allows AI applications to:

• 🔌 Connect to external data sources and tools
• 🛠️ Execute actions in a standardized way
• 🔄 Maintain consistent communication patterns
• 🌐 Enable tool interoperability across different AI systems

Key Concepts

1. MCP Server: Exposes tools/capabilities that can be called by clients
2. MCP Client: Consumes tools from MCP servers
3. JSON-RPC Protocol: Communication standard for request/response patterns
4. Tools: Individual capabilities exposed by the server (e.g., weather, web search)

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🏗️ Architecture

┌─────────────────────────────────────────────────────────────┐
│                        USER INPUT                            │
│                 "What's the weather in Mumbai?"              │
└──────────────────────┬──────────────────────────────────────┘
                       │
                       ▼
┌─────────────────────────────────────────────────────────────┐
│                   LANGGRAPH AGENT                            │
│  ┌──────────────┐         ┌──────────────┐                  │
│  │   Routing    │────────▶│   Response   │                  │
│  │     Node     │         │    Node      │                  │
│  └──────┬───────┘         └──────────────┘                  │
│         │                                                     │
│         │ Uses OpenAI to determine:                          │
│         │ - Which tool to use                                │
│         │ - Extract parameters                               │
└─────────┼─────────────────────────────────────────────────────┘
          │
          ▼
┌─────────────────────────────────────────────────────────────┐
│                    MCP CLIENT                                │
│  - Manages connection to MCP server                          │
│  - Sends JSON-RPC requests                                   │
│  - Receives and processes responses                          │
└──────────────────────┬──────────────────────────────────────┘
                       │
                       │ JSON-RPC over STDIO
                       │
                       ▼
┌─────────────────────────────────────────────────────────────┐