How to Design a Production-Ready MCP Server — A Universal Blueprint

A comprehensive system design guide for building production-ready MCP (Model Context Protocol) servers. Covers the Client→Host→Server architecture built on JSON-RPC 2.0, the three core primitives (Tools, Resources, Prompts) and when to use each, transport selection (STDIO vs HTTP), bounded context design to avoid god-server anti-patterns, tool design rules including Zod schema validation, idempotency, statelessness, and typed error returns, token efficiency strategies to avoid bloating AI context windows, three-tier caching and async task patterns for performance, security boundaries (path traversal, rate limiting, OAuth), observability with structured logging and health checks, and a monorepo structure for scaling multiple servers. Includes a universal pre-ship checklist.