Modular Hexagonal DDD — ONE-SHOT APPLY (cakephp)

Self-contained. An AI agent should fetch this file only and execute it. Core version: 1.0.0-draftShort HTML entry: /cakephp · This file: /apply/cakephp.full.mdAI-neutral: assistant files are optional; architecture does not require any AI vendor. Host baseline researched: see Part C header (versions as of 2026-08).

0. Agent mandate

You are bootstrapping a cakephp application repository (not the docs site).

Treat this document as the complete working standard for this session.
Execute Part D in order after reading Parts A–C.
When writing module code, obey Part B (Core) and Part C (host).
Do not create a git commit unless the human explicitly asks.
Rename illustrative contexts Ordering, Warehouse, Directory, Identity to the human’s domains.
If AI vendor is none, skip Part E.

Programmer prompt

Apply Modular Hexagonal DDD from <ORIGIN>/apply/cakephp.full.md
AI assistant: <cursor|claude|gemini|copilot|generic|none>
Bounded contexts: <list>
Do not commit unless I ask.

Part A — Design test

If the peer module is deleted and replaced by HTTP, does this module’s Application and Domain still compile?

Part B — Complete Core architecture

Build applications as replaceable bounded-context modules using Hexagonal Architecture (ports & adapters) + DDD. This docs site is the sole canon; consuming repos keep thin pointers, not a forked essay.

B2. Module layout (MUST)

{Module}/
  Application/     # UseCases, Application DTO, Providers / composition root
  Domain/          # Entities, Ports, Events, Enums, Domain DTOs
  Infrastructure/  # Persistence adapters, ExternalServices (ACL), Config, listeners
  UI/              # Controllers, Routes, validation, admin UI, console
Shared/            # Promoted technical ports/adapters only (after promote rule)

Host roots vary (app/Modules, src/Modules, packages). Roles do not.

B3. Strictness ladder (MUST)

Strictness	Area	Allowed	Forbidden
Hardest	Domain	Own Domain types + Shared kernel ports	Other modules; host facades/helpers; ORM; framework traits on Domain Events
Strict	Application Use Cases / App DTOs	Own Domain + Shared ports	Facades, ORM, foreign Application/Domain, peer `*ModuleInterface`
Relaxed	Composition root	Container binds, routes, config merge	Business rules
Outer	Infrastructure & UI	Framework, ORM, HTTP, ACL adapters, admin	Leaking ORM/foreign Domain into Domain/Use Cases

Dependency direction: Domain ← Application ← Infrastructure/UI. Ports in Domain; adapters in Infrastructure.

B4. Golden flow (MUST)

UI → Application DTO → first-level *UseCase::__invoke
  → Domain (Entity / Domain service)
  → Domain Port
  → Infrastructure adapter (ORM / ACL / HTTP)
  → back as Entity / result
  → UI presents

B5. Use Cases & DTOs (MUST)

First-level: Application/UseCases/{Capability}/SomethingUseCase with single public __invoke.
Nested helpers: no UseCase suffix; not called from UI.
Mirror {Capability}/ for DTOs and Ports.
ACL need ports: Domain/Ports/Acl/. Module façades: Domain/Ports/Module/.
Never create a literal Feature/ directory.
Application DTO = UI/CLI input. Domain DTO = intra-module only.
Other modules never call Use Cases — only ACL / Events.

B6. Cross-module bridges (MUST)

Application/Domain of A never import Application/Domain of B.

Need	Bridge
Peer answer now	Sync ACL: local `{Need}PortInterface` → Infra ACL adapter → thin peer `{This}ModuleInterface`
Peer reacts later	Async Domain Event → consumer Infra translation listener → inbound Use Case

Mapping only in ACL adapter; façades thin + HTTP-mappable; Prefer ACL validate before local commit.
Events: pure Domain class; Shared EventDispatcherInterface; eventId + occurredAt + schemaVersion + rich happy-path payload; idempotent consumers; no Domain re-fetch on happy path; prefer outbox.
No cross-module write transaction. Reports: ACL reads or owned projections.

B7. Shared promote rule (MUST)

Situation	Where
Tech used by one module	That module’s Infrastructure
Same tech used by ≥2 modules	Promote to Shared
Cross-module business concept	Never Shared — ACL / Events

Typical Shared: DomainException, DatabaseTransactionInterface, EventDispatcherInterface, ClockInterface, ConfigReaderInterface, Ensure.

B8–B9. Persistence & UI (MUST)

Map persistence records ↔ Domain Entities in Infrastructure; never leak ORM into Use Cases/Domain.
UI: authorize → DTO → Use Case → present.

B10. Decision tree

Only this module? → Golden flow
Need peer now? → ACL
Peer later? → Event
Multi-step? → Orchestration (still ACL+Events)
Report across contexts? → Projection / ACL read
Tech in 2+ modules? → Shared
Business in 2+ modules? → ACL/Events — never Shared

B11. Anti-patterns

Peer imports in Use Cases; god façades; thin-ID events; Shared business enums; ORM in Domain; Entity extends ORM; literal Feature/; cross-module DB TX; ORM joins across modules for policy.

B12. Examples

Ordering, Warehouse, Directory, Identity only — rename to your domains.

B13. Quality assertions

Boundary tests must fail CI if: foreign Application/Domain imports; peer *ModuleInterface in Use Cases; ORM/facades in Domain/Use Cases; literal Feature/ folders. Also: behaviour tests, formatter, static analysis, event idempotency.

Part C — CakePHP host mapping


Target	CakePHP 5.4.x (e.g. 5.4.1 as of 2026-07; PHP 8.2–8.5)
Docs	https://book.cakephp.org/5/ · Plugins · Dependency Injection
App skeleton	`cakephp/app` ^5.4
Adapter HTML	`<ORIGIN>/v1/adapters/cakephp`

Map each bounded context to a CakePHP plugin (or src/{Module} namespaces) containing Core layers. CakeORM Table / Entity classes are Infrastructure, not Domain Entities.

Core	CakePHP 5.4 place
Module root	`plugins/{Module}/` (plugin) or `src/{Module}/`
Shared	`plugins/Shared/` or `src/Shared/`
Composition root	`Application::services()` and plugin `Plugin::services(ContainerInterface)` — bindings only
Persistence	`Infrastructure/Persistence/` — `Table` classes + Cake `Entity` maps → Domain Entities in repositories
ACL adapter	Infra service registered in DI; inject local port into Use Cases
Translation listener	Queue listener / Cake event subscriber in Infra → inbound Use Case
UI	Controllers in plugin `UI` / `Controller` calling Use Cases; no business rules in Tables

ORM quarantine

Do not treat Cake Entity as Domain Entity.
Prefer constructor injection of ports into Use Cases.
From CakePHP 5.3+, TableContainer delegate enables injecting *Table into Infra services — still keep Tables out of Domain/Use Cases (DI / TableContainer).

DI example

// plugins/Ordering/src/OrderingPlugin.php
public function services(ContainerInterface $container): void
{
    $container->add(WarehouseAvailabilityPortInterface::class)
        ->setConcrete(WarehouseAvailabilityAclAdapter::class);
    $container->add(PlaceOrderUseCase::class)
        ->addArgument(WarehouseAvailabilityPortInterface::class)
        /* + other ports */;
}

Enable plugins in Application::bootstrap().

Events

Wrap Cake events or a queue in Shared EventDispatcherInterface adapter.
Consumer plugin Infra subscriber/listener → Use Case; idempotent eventId.

Tooling

PHPUnit; PHPStan; bin/cake bake only into Infrastructure/UI paths you specify.
Rector/Cake upgrades: keep Domain pure when upgrading 5.x minors.

Part F — Sketch

Ordering controller → Use Case → ACL port → Warehouse plugin façade service; async subscriber in Warehouse plugin.

Part G — Done checklist (standard)

Part E — Assistant files (optional)

Skip if AI vendor is none.

Create shared folder:

.ai/modular-hexagonal-ddd/
  ARCHITECTURE.full.md   # copy of the host one-shot you fetched
  RULES.core.md
  SKILL.md
  CHECKLIST.md
  cakephp-host.md         # host-only notes from Part C

E0 — RULES.core.md

# Modular Hexagonal DDD — Core rules
Canon: <ORIGIN>/v1/core (1.0.0-draft)
One-shot: <ORIGIN>/apply/cakephp.full.md
Local: .ai/modular-hexagonal-ddd/ARCHITECTURE.full.md

1. Domain hardest: no host framework, ORM, other modules.
2. Use Cases: own Domain + Shared ports only.
3. Cross-module: ACL or Domain Events only.
4. Thin façades; rich events (eventId, schemaVersion); idempotent consumers.
5. No cross-module write TX; ACL validate-before-commit.
6. Shared = technical ≥2 modules only.
7. *UseCase + __invoke; no literal Feature/ folders.
8. Design test: peer→HTTP, Application/Domain still compile.

E1 — SKILL.md

---
name: modular-hexagonal-ddd
description: Enforce Modular Hexagonal DDD. Modules, ACL, Events, Shared, Use Cases.
---
Follow .ai/modular-hexagonal-ddd/ARCHITECTURE.full.md

E2 — CHECKLIST.md

- [ ] First-level *UseCase entry
- [ ] App DTO → __invoke
- [ ] I/O via Domain ports
- [ ] No ORM/facades in Application/Domain
- [ ] Sync peer → local ACL port → thin façade
- [ ] Async → rich event + translation listener → inbound UC
- [ ] Idempotent eventId
- [ ] No cross-module DB TX
- [ ] No foreign Application/Domain imports
- [ ] Shared only technical ≥2
- [ ] No Feature/ directories
- [ ] Replaceability test = yes