What is MCP? A Guide for Developers

❌ Without MCP:
Agent 1 (ChatGPT) ──→ Custom SDK for GitHub
Agent 2 (Claude) ──→ Different API wrapper for GitHub
Agent 3 (Custom) ──→ Yet another integration

Result: Fragmented, hard to maintain, duplicated code

✅ With MCP:
Agent 1 ──┐
Agent 2 ──┼─→ MCP Standard ──→ GitHub (Single integration)
Agent 3 ──┘
Agent 4 ──┼─→ MCP Standard ──→ Slack (Single integration)
...

┌──────────────────┐
│   Your AI Agent  │
│   (Claude, GPT)  │
└────────┬─────────┘
         │
         │ "List my GitHub issues"
         ↓
┌──────────────────────────┐
│  MCP (Protocol Layer)    │
│  Standard message format │
└────────┬────────────────┘
         │
         │ Convert to GitHub API call
         ↓
┌──────────────────┐
│  GitHub Service  │
│  (via MCP Server)│
└────────┬─────────┘
         │
         │ Returns: [Issue 1, Issue 2, ...]
         ↓
┌──────────────────────────┐
│  Agent receives results  │
│  in standard MCP format  │
└──────────────────────────┘

MCP Server = Tool Provider

MCP Client = Tool Consumer

# You need to write custom integrations for each agent

# For Claude
from anthropic import Anthropic
import github_sdk

client = Anthropic()
github_client = github_sdk.GitHub(token="...")

def github_tool(action, params):
    # Custom integration code...
    pass

# For custom Agent
import agent_framework
github_integration = custom_github_wrapper(...)

# For Copilot
# Different integration needed...

# Single MCP server, works everywhere

# GitHub MCP Server
server = MCPServer("github-mcp")
server.add_tool("create-pull-request", handle_pr_creation)
server.add_tool("list-issues", handle_list_issues)

# Now ANY agent can use it:
# - Claude
# - Custom agents
# - Copilot
# - Agent-CoreX

Agent Request:
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "create-pull-request",
    "arguments": {
      "repository": "owner/repo",
      "title": "New feature",
      "from_branch": "feature/x",
      "to_branch": "main"
    }
  }
}
        ↓
MCP Server (GitHub):
1. Receive request
2. Validate parameters
3. Call GitHub API
4. Format response
        ↓
MCP Response:
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "success": true,
    "data": {
      "pr_number": 123,
      "pr_url": "https://github.com/owner/repo/pull/123"
    }
  }
}
        ↓
Agent receives result and continues reasoning

{
  "method": "initialize",
  "params": {
    "capabilities": {
      "tools": true,           // Server has tools
      "resources": true,       // Server has resources
      "prompts": true,         // Server has prompts
      "logging": true          // Server supports logging
    }
  }
}

{
  "method": "tools/list",
  "result": {
    "tools": [
      {
        "name": "create-pull-request",
        "description": "Create a GitHub PR",
        "inputSchema": { ... }
      }
    ]
  }
}

{
  "method": "tools/call",
  "params": {
    "name": "create-pull-request",
    "arguments": { /* tool-specific params */ }
  }
}

┌────────────────────────────────────────────────────────┐
│                  Your AI Agent                         │
│          "Deploy to production and notify"             │
└─────────────────────┬────────────────────────────────┘
                      │
        ┌─────────────┴─────────────┐
        │                           │
        ↓                           ↓
┌──────────────┐            ┌──────────────┐
│  Retrieval   │            │   Direct     │
│  (Semantic)  │            │  Execution   │
└──────┬───────┘            └──────┬───────┘
       │                           │
       │ "Tools for deployment"    │ "Run this specific tool"
       ↓                           ↓
    ┌──────────────────────────────────────┐
    │      MCP Manager                     │
    │ - Server routing                     │
    │ - Auth & credentials                 │
    │ - Error handling                     │
    └──────────────┬───────────────────────┘
                   │
        ┌──────────┼──────────┐
        │          │          │
        ↓          ↓          ↓
    ┌────────┐  ┌───────┐  ┌─────────┐
    │ GitHub │  │ Slack │  │Terraform│
    │  MCP   │  │  MCP  │  │   MCP   │
    └────────┘  └───────┘  └─────────┘
        │          │          │
        ↓          ↓          ↓
   GitHub API  Slack API  Terraform CLI