Typed boundaries are a product feature

Types are not only for developer experience. Good types capture product decisions in code.

Boundaries reduce interpretation work

APIs, forms, state changes, and jobs all carry assumptions. If those assumptions are hidden, every change takes longer.

Typed boundaries make the assumptions visible. They help answer simple questions: Can this field be missing? Who owns this status? Is this date shown to users?

Types should describe the domain, not just the transport

Good types should use product words. A ReviewStatus type is better than a plain string because it names the states the product supports.

Those names show up in tests, docs, and conversations. They make the system easier to discuss.

The practical test

If a new teammate can read the types and understand the product rules, the boundaries are doing their job.