Using CLAUDE.md, skills/, agents/, hooks, MCP, and settings.json transforms Claude Code from a chatbot into a senior engineer that remembers conventions, runs tests, refactors, and splits work.

A single CLAUDE.md file based on Karpathy's observations prevents Claude Code from guessing, over-engineering, and touching unintended code.

The engineer who built Claude Code released a 28-minute video covering prompt writing techniques including CLAUDE.md files, memory shortcuts, parallel sessions, and prompting patterns.