When I first opened Claude Code on a real project, it felt like hiring a brilliant junior who had read every book but never shipped anything. It could write code fast, but it would forget my conventions halfway through a session, run a migration without asking, and "fix" a bug by deleting the failing test.
After a few weeks of tuning, it now behaves like a small senior team: it plans before it codes, reviews its own work, writes tests, and refuses to run anything destructive. The difference wasn't a better model. It was a better setup — a CLAUDE.md, a set of focused subagents, a couple of MCP servers, and two small hooks.
Here is exactly how that setup works, so you can build your own.
1. CLAUDE.md is the contract, not a wishlist
CLAUDE.md is the file Claude Code reads automatically at the start of every session. Most people treat it like a README. It works far better as a contract: short, specific, and written in always/never terms the agent can't misread.
