MCP vs skill

MCP servers and skills solve different problems and are not direct alternatives. An MCP server gives Claude new capabilities by providing a connection to systems it cannot otherwise reach, such as a database, issue tracker, or monitoring dashboard. It is code you run, connected over stdio, HTTP, SSE, or WebSocket, configured with claude mcp add and stored in .mcp.json. A skill, conversely, gives Claude knowledge and procedure in the form of a SKILL.md file containing instructions that Claude already has the tools to carry out. It is markdown, requires no separate process, and its body loads into context only when relevant. A rough test: if Claude cannot physically reach the target system, you need an MCP server; if Claude can reach it but performs the job poorly or inconsistently, you need a skill. These concepts compose: a skill can define the procedure for driving an MCP server's tools effectively, and a plugin can bundle both. The cost profile differs: MCP tool definitions load into context when the server is connected, whereas a skill's body remains out of context until invoked. Do not assume one replaces the other. For example, MCP Builder helps build MCP servers, while Skill Creator helps build skills. Understanding the distinction is key to effective agent-skill design, avoiding confusion with skill-vs-prompt or progressive-disclosure patterns.