After getting a few things set up, I hit the "Publish" button, excited to see the changes live. Instead, I was greeted with a big, red error message: `error in createBuildConfig: error in validateSignedURLBuildConfig: build config is missing required build step fetch`.

My first reaction was confusion. The error looked like internal system jargon. I hadn't touched anything related to a "build config" or "signed URL." As someone new to this, it's easy to assume the problem is complex and hidden deep within the system.

But the truth is, error messages, even cryptic ones, are usually your friend. The key phrase was "build config is missing." I was working in a new environment, and I'd forgotten a basic step: you have to tell the server how to build your app. It needs instructions. The fix was adding a small configuration file (`apphosting.yaml`) with a few lines telling it to run `npm install` and `npm run build`. It was a simple, practical reminder: before you dive deep, read the error message carefully. Often, it's telling you exactly what's wrong, even if it's dressed up in confusing language.