domain-model

name

domain-model

description

Creates or modifies domain types in src/domain/ — value objects, discriminant unions, and aggregate roots. Use when adding a new domain concept, defining invariants for an existing type, or placing a shared discriminant union that is used across multiple use-cases. Do NOT use for orchestrating I/O or business logic — use `use-case` instead. Do NOT use for infrastructure concerns — use `adapter` instead.

Domain Model

Builds and places the typed vocabulary of the application: value objects, discriminant types, and aggregate roots that live in src/domain/models/. The domain layer must never import from application/ or infrastructure/.

Available actions

#	Action	Role	Input
01	choose-shape	Decide between value object, discriminant type, or aggregate	concept description
02	define-invariants	Encode readonly fields, validation, factory	chosen shape from 01
03	place	Pick canonical file location, add named export	defined type from 02
04	test	Write unit tests for the domain type	placed type from 03

Default flow

01 → 02 → 03 → 04

Transversal rules

• All domain types must be free of application/ and infrastructure/ imports.
• All fields are readonly; return new instances for mutations.
• Never inline a discriminant union used in ≥2 use-cases; place it in src/domain/models/.
• Named export only, no default export.
• File name is kebab-case.ts.
• Validate invariants in constructor or static factory; throw a typed domain error on invalid input.
• Module-level const in CONSTANT_CASE for any literal used more than once.

References

• references/value-objects.md — value object conventions (readonly, equals, constructor params)
• references/discriminant-types.md — discriminant union placement rules and canonical locations
• references/manifest.md — aggregate root conventions for the Manifest model

Invariant rules

• references/value-objects.md — authoritative value object rules
• references/discriminant-types.md — authoritative discriminant type rules