Domain Entity UUIDv4 IDs

Goal

Represent domain entity identifiers with UUIDv4.

When the programming language or standard library provides a built-in UUID type, prefer that type for domain entity IDs. When no such built-in type exists, use string for domain entity IDs and keep UUIDv4 generation and validation explicit.

Treat this skill as identity-format guidance for domain entities. It determines the identifier format (UUIDv4) and the underlying type (built-in UUID or string). Whether to wrap that underlying type in a distinct type per domain entity — such as OrderId or CustomerId — is a separate concern handled by the domain-entity-typed-ids skill.

The key question is whether the edited code defines, carries, validates, stores, serializes, or exposes the identifier of a domain entity.

What Counts as In Scope

Apply this skill to code that does one or more of these things: