Module dependency stack

Question and use cases

Protocol enters through the host; dependencies point inward to domain contracts.

Use this stack to decide where new behavior belongs inside a module.

Use the diagram during design review, incident diagnosis, code walkthroughs, and onboarding. It intentionally omits classes and projects unrelated to the focused question, so read it together with the source entry point and related topic pages.

This page covers only the named responsibilities and relationships; consult the relevant module documentation for capabilities not shown here.

Reading path

1. Step 1: Start at the protocol edge and identify translation-only responsibilities.
2. Step 2: Move inward to the application use case and domain invariant.
3. Step 3: Read infrastructure as an outward adapter that implements inward-facing ports.

Do not skip arrow direction, numbering, or group titles: they express dependency or time direction, execution order, and responsibility boundaries. If the diagram differs from current source or accepted architecture decisions, correct the generated catalog immediately.

Legend and notation

This is a LAYER STACK diagram. Use that form to understand the layout, then test your interpretation against the source facts below.

Key relationships and design meaning

Relationship 1

Source fact: Endpoints translate HTTP and delegate to an application use case.

Architectural meaning: Protocol changes should affect endpoint translation without forcing domain rules to understand HTTP concerns.

Review action: Could the rule be tested without HTTP, an ORM, or a vendor SDK?

Relationship 2

Source fact: Aggregates, invariants, typed results, and domain events stay in the domain boundary.

Architectural meaning: Keeping invariants in the domain gives commands, jobs, tests, and future protocols the same behavioral source of truth.

Review action: Is the dependency pointing toward policy rather than technology?

Relationship 3

Source fact: Infrastructure implements application-facing ports and may depend on vendors or databases.

Architectural meaning: Application-owned ports make technology replacement an adapter concern instead of a use-case rewrite.

Review action: Is a separate persistence model justified by real asymmetry?

Design review questions

Answer each question when reviewing or implementing a related change. If code, tests, or an ADR cannot support the answer, do not decide from the diagram alone.

• Could the rule be tested without HTTP, an ORM, or a vendor SDK?
• Is the dependency pointing toward policy rather than technology?
• Is a separate persistence model justified by real asymmetry?

How to use the answers

1. Identify the single owner of the capability or rule.
2. Confirm that dependency, call, or event direction does not reverse ownership.
3. Capture the conclusion with an automated test or repeatable command.

Boundaries and common mistakes

Boundary 1

A separate persistence model is an explicit asymmetric exception, not a mandatory layer.

• Do not infer: A connector in the diagram does not mean every implementation uses synchronous calls, a shared transaction, or shared data ownership.
• Review requirement: Is the dependency pointing toward policy rather than technology?

Boundary 2

Do not place business branching in endpoints, repositories, or mapping code.

• Do not infer: A connector in the diagram does not mean every implementation uses synchronous calls, a shared transaction, or shared data ownership.
• Review requirement: Is a separate persistence model justified by real asymmetry?

Source verification and regeneration

The primary verification entry point is .ai/constraints/architecture-rules.md. Inspect it and its direct references before regenerating diagram assets and pages.

# Regenerate bilingual SVG, standalone HTML, and documentation pages
npm run diagrams

# Check locale pairs, references, safety attributes, accessibility, and canvas bounds
npm run verify:diagrams

# Confirm that generation changed only the intended diagrams and pages
git diff -- scripts/diagrams diagram-sources public/diagrams src/content/docs

# Verify internal links, MDX structure, and professional depth gates
npm run verify:docs
npm run audit:docs-depth

Change-completion checklist

• Responsibilities, order, states, and relationships match current source.
• Every new element helps answer this page’s question instead of turning the diagram into an inventory.
• Arrows have explicit direction and semantics without implying nonexistent synchronous or transactional guarantees.
• Chinese and English titles, labels, facts, and boundaries remain semantically equivalent.
• The diagram remains readable on narrow screens, in fullscreen, and while zoomed, with no overlap or overflow.
• Relevant architecture tests, integration tests, or verification commands have run.
• If a long-lived constraint changed, its ADR or architecture documentation is updated.

Continue reading

• Architecture overview
• All architecture diagrams
• Platform modules