Explicit Boundaries

Kind: principle

Layer: Domain Modeling

Record: architecture:explicit-boundaries

Severity: mandatory

Scope: module, component, service, domain

Canonical: Ontology

A design rule that each module declares its public interface and owner, and other modules reach it only through that interface.

Listed in Architecture principles, after Anti-Corruption Layer and before Aggregate.

Requires

• Stable Interfaces
• Ownership

Reinforces

• Modularity
• Encapsulation

Enables

• Replaceability
• Governance

Conflicts with

• Boundary Leakage

In tension with

• Cross-Cutting Concerns

Tensions

• Explicit Boundaries / Cross-Cutting Concerns

Violated by

• Boundary Leakage
• Inappropriate Intimacy

Refactored by

• Move Behavior to Its Owner
• Define Contract
• Restrict Exports

Severity

• mandatory

Category

• Domain Architecture

Enforced by

• codemods/entrypoints/specifier.entrypoint.ts
• rules/eslint/closure-build-script-unimported.eslint.rule.ts
• rules/eslint/closure-no-cross-member-relative.eslint.rule.ts
• rules/eslint/closure-standalone-script-imported.eslint.rule.ts

Required by

• Bounded Context
• Aggregate
• Single Responsibility Principle
• Separation of Concerns
• High Cohesion
• Independence

Reinforced by

• Context Mapping
• Declared Jurisdiction

Linked from

• When rules collide
• Principles are typed
• Architectural rules and principles
• Anti-patterns
• Domain Architecture
• Contracts / Interfaces / Compatibility
• Core Modular Design
• Security / Privacy / Compliance / Governance
• Taxonomy / Classification / Naming
• Contracts / Interfaces / Compatibility
• Core Modular Design
• Core Vocabulary
• Severity levels
• The resolutions