• Open standard connecting AI apps to tools & data — "USB for AI"
• Build one MCP server, use it from Claude Code, desktop, IDEs, your apps
• Primitives: tools, resources, prompts; local (stdio) or remote (HTTP)
MCP replaces N×M custom integrations (every app × every tool) with one protocol. An MCP server exposes tools/resources/prompts; any MCP client consumes them. Your "query the database" tool, written once, works in Claude Code, Claude desktop, and your own product.