Look, I've been using Claude Code for a few months now and I just realized most people are doing it backwards. Everyone's just throwing vague prompts at it like "build me a login system" and then spending forever going back and forth fixing stuff. There's a better way. Write the damn spec first. I'm serious. Before you even open Claude Code, spend 20 minutes writing out what you actually need. Requirements, edge cases, how the API should work, what errors to handle. Just a markdown file. Nothing fancy. Then (and this is the part nobody talks about) you point Claude Code directly at that spec file. "Implement the auth service in auth-spec.md." That's it. What happens next is honestly kind of wild. It reads the whole thing, sometimes asks you questions if something's unclear, then just builds it. Multiple files, proper error handling, tests that actually make sense. Because it knows exactly what you want. No more asking - actually can you change this fifteen times. No more - I forgot to mention we need to handle OAuth too. The spec is right there. And here's the thing that sold me: your specs don't disappear into some Google Doc graveyard. They live with your code. When you need to refactor three months later, the spec is still there telling you what the hell you were thinking. Try it once. Write a proper spec, save it as a .md file in your project, and tell Claude Code to build from it. You'll get why everyone who does this won't shut up about it.