scott-ddd-refactor

Model workflows as explicit state transitions by replacing primitives with semantic types and applying boundary parsing rules. This keeps core logic pure and deterministic by ensuring only valid typed transitions are allowed.

You need type-driven design when transforming codebases that require explicit state modeling and boundary isolation. It is essential for projects where preventing illegal states and maintaining strict domain correctness are critical.

Parse at boundaries by isolating external data conversion rules at the system edges before data enters the core. This boundary parsing ensures internal domain logic remains pure, deterministic, and free of unvalidated primitive types.

The best way to migrate safely is using a phased refactor playbook with a decision matrix. This guides the evolution by auditing domain concepts first, then replacing primitives with semantic types, and finally migrating workflows into explicit state transitions.

A domain error taxonomy guides safe evolution by categorizing domain-specific failures systematically. This structured error classification directs the refactoring process to ensure type-safe boundaries and explicit state transitions handle errors correctly.