It's a huge mistake to start building with Claude without mapping out a project in detail first, by hand. I built a pretty complex device orchestration server + agent recently, and before I set Claude to actually coding I had ~3000 lines of detailed design specs across 7 files that laid out how and what each part of the application would do.

I didn't have to review the code for understanding what Claude did, I reviewed it for verifying that it did what it had been told.

It's also nuts to me that he had to go back in later to build in tests and validation. The second there is an input able to be processed, you bet I have tests covering it. The second a UI is being rendered, I have Playwright taking screenshots (or gtksnapshot for my linux desktop tools).

I think people who are seeing issues at the integration phase of building complex apps are having that happen because they're not keeping the limited context in mind, and preempting those issues by telling their tools exactly how to bridge those gaps themselves.