Over the past few months I've been building with Cursor, Claude Code, and Codex - same tools a lot of builders are running right now. The pace is genuinely wild. I've shipped MVPs for friends where we went from a rough PRD to a working demo in a single day: auth wired up, database in place, deployed, link sent before midnight. Some of it fully vibe-coded. Some of it structured. All of it fast.
You're seeing this everywhere now. Builders spinning up entire products over a weekend, sometimes over an afternoon, because the tools finally keep up with the idea in your head.
And here's the thing people undersell: AI coding agents are actually pretty good at following engineering principles - when they have something to follow. Hand them a PRD, point them at your conventions, set a few non-negotiable rules, and they mostly stick to it. They'll reuse your components instead of inventing new ones. They'll write tests if tests are part of the standard. They won't skip the boring obvious stuff if the boring obvious stuff is written down somewhere they load every session.
The gap I kept hitting wasn't the coding. It was what happened to the decisions along the way.
When you move this fast, you make dozens of small calls in chat: which auth flow, which database, what "done" means for this feature, whether this module owns that boundary. The code commits to the repo. The reasoning usually doesn't. It stays in a thread that gets compacted, or a session that ends, or your head - which is a rough place to store architecture when you're juggling three builds at once.
