Build AI-agent-optimized Model Context Protocol (MCP) servers following the MCP Excellence Standard. Use when creating new MCPs, enhancing existing MCPs, wrapping APIs as MCPs, or when the user mentions MCP, Model Context Protocol, or wants to build tools for AI agents. This skill ensures MCPs are token-efficient (returnOnlyIds, compact mode, pagination), include composite operations (search_and_action, get_or_create), handle errors properly (partial success, structured errors), and implement safety guardrails (dryRun, confirmation tokens, batch limits).