Field notes

When a rich domain gets expensive

A well-modeled domain lets AI write code that reads like a sentence. Changing that domain is where the bill shows up.

Marcelo NúñezBackend · domainLesson

Give the AI a precise enough business rule and it writes code you can read out loud: a voucher is valid because it has at least one line, the concepts match, the totals match the lines. Secure on every side. Beautiful, and cheap to build.

The catch: a rich domain is expensive to change. Touch it and it ripples everywhere. So the model has to fit the business, not your habit. A process that is really a hand-off, analyze then report then store, doesn't want an object graph. It wants a functional pipeline. Choosing that correctly is the senior call no agent makes for you.

This is how we'd run your backlog.

Bring a real one to a Sprint Zero and watch the loop close on your code.