The Protocol That Wants to Be USB-C for AI — How MCP Changes Everything

Connecting 3 AI apps to 3 tools used to require 9 custom integrations. Each model vendor needed its own connector format. MCP changes that by standardizing the interface between AI hosts and external tools. What MCP standardizes MCP is an open protocol for AI-to-system connectivity, typically transported over JSON-RPC 2.0. It standardizes: Tools (callable functions) Resources (read-only references) Prompts (reusable templates) The practical result: build once, reuse across hosts. Architecture Host: Claude Desktop, Claude Code, Cursor, etc. Client: per-server session manager inside the host Server: wraps external systems like GitHub, Postgres, Drive Lifecycle: initialize → exchange messages → close. MCP and function calling MCP does not replace function calling. It unifies it across vendors. Tool schemas, parameters, and result envelopes become portable. MCP vs RAG RAG = retrieval-first knowledge augmentation (mostly read path) MCP = operational orchestration (read/write/call side effec