MCP Developer Quick Start Guide
You're a developer. You don't need the hand-holding. You need architecture, APIs, and code examples. This is the technical quick start: how MCP works under the hood, how to use existing servers, and how to build your own.
Architecture Overview
The protocol defines a standard way for the Client and Server to handshake, negotiate capabilities, and exchange messages. The mostly widely used transport today is stdio (standard input/output), meaning the Client spawns the Server as a subprocess.
The 3 Primitives
MCP exposes three main capabilities to the LLM.
"Read-only Data"
File contents, database rows, API responses. The server provides a URI scheme (e.g. postgres://) and the client reads it.
"Executable Functions"
Functions the LLM can call. They take JSON arguments and return text/image results. (e.g. execute_sql_query).
"Reusable Context"
Pre-written prompt templates that help users use your server effectively (e.g. "Analyze Database Schema").
Configuration
Clients (like Claude Desktop) need to know how to start your server. This is done via claude_desktop_config.json.
Building a Hello World Server
The easiest way to start is using the TypeScript SDK.
# 1. Scaffold a project
npm create @modelcontextprotocol/server@latest# 2. Define a Tool (index.ts)
When you run this server and connect it to Claude, the model will see a tool named calculate_sum and know how to use it structurally.
Debugging & Inspector
Because MCP runs over stdio, you can't just console.log to debug (it will break the JSON protocol).
- Use Stderr:
console.error()logs will show up in the Claude logs without breaking the protocol. - MCP Inspector: Use the official inspector to test your server in the browser without Claude.
Resources
Ready to go deeper?
Build the Future of Context
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