What Actually Changes When You Build With Coding Agents (4 Shifts I Wish I'd Known Sooner)

I spent a chunk of weekends over the past year using coding agents as my primary engineering partner, building a full-stack enterprise app end-to-end. Spring Boot on Java 21. React 19. PostgreSQL. Playwright tests. Jenkins CI/CD. The whole thing layered the way you'd build any serious system: framework utilities first, reusable component library, UI shell, then product pages on top. The app itself wasn't the point. I built it because I wanted to know, at a practitioner's level, what actually changes when you work this way - not what the s and quick-takes claim.