What's the difference between MCP and Claude Skills?

MCP gives Claude access to external tools and data that live outside the conversation; Skills teach Claude how to use what it already has, loading a folder of instructions only when a task calls for them.

The cost pattern is the real difference. Once an MCP server is connected, its tool definitions sit in context whether or not a given turn uses them, and a large integration can cost tens of thousands of tokens just describing what it offers before the model ever emits a single tool call. A Skill stays off to the side until the model judges a task matches it, so having many installed costs nothing until one actually fires. MCP is the way to reach something live: a ticket system, a database, a calendar. A Skill is the way to hand over a repeatable procedure, a checklist or a house style, without paying for it on every turn. Most real setups run both, one supplying access and the other supplying the know-how to use it well.