Claude Code Customization Guide: Rules vs Skills vs Subagents vs MCPsJANUARY 5, 2026Claude Code Customization: When to Use Rules, Skills, Subagents, and MCPs Claude Code has four internal configuration layers: CLAUDE.md (master config), Rules (domain knowledge), Skills (workflows), and Subagents (autonomous tasks). Plus MCPs as external bridges to tools like GitHub, databases, and Slack. Internal layers shape how Claude thinks; MCPs extend what Claude can reach. Cl
