# Boundary Leakage

> A defect in which internal, persistence or vendor types cross an architectural boundary.

Record: `architecture:boundary-leakage`
Kind: anti-pattern
Layer: [Enforcement Core](https://banes-lab.com/records/layer/enforcement-core.md)
Severity: discouraged
Scope: modularity, model_governance
Canonical: https://banes-lab.com/ontology#architecture-boundary-leakage

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Shared Mutable State](https://banes-lab.com/records/architecture/shared-mutable-state.md) and before [Manual-Only Governance](https://banes-lab.com/records/architecture/manual-only-governance.md).

## Repair

- Refactored by: restrict_exports, introduce_DTO, add_adapter, add_facade, enforce_import_rules
- Detected by: internal_package_imported_externally, database_entity_exposed_as_API, vendor_type_in_domain, private_module_used_by_other_module
- Violated by: Permit internal models, infrastructure types, persistence structures, or private module APIs to cross intended architectural boundaries.
- Measured by: internal types exposed across boundaries
- Enforced by: export and import restrictions, boundary architecture tests

## Severity

- [discouraged](https://banes-lab.com/records/vocabulary/severity-discouraged.md)

## Category

- [Anti-patterns](https://banes-lab.com/records/architecture-category/anti-patterns.md)

## Force

- [Model governance](https://banes-lab.com/records/force/model-governance.md)
- [Modularity](https://banes-lab.com/records/force/modularity.md)

## Detected by

- [codemods/entrypoints/specifier.entrypoint.ts](https://banes-lab.com/source/governance/codemods/entrypoints/specifier.entrypoint.ts.md)
- [rules/eslint/closure-no-cross-member-relative.eslint.rule.ts](https://banes-lab.com/source/governance/rules/eslint/closure-no-cross-member-relative.eslint.rule.ts.md)
- [rules/eslint/closure-no-platform-product-import.eslint.rule.ts](https://banes-lab.com/source/governance/rules/eslint/closure-no-platform-product-import.eslint.rule.ts.md)

## Negated by

- [Explicit Boundaries](https://banes-lab.com/records/architecture/explicit-boundaries.md)

## Linked from

- [Principles are typed](https://banes-lab.com/software-architecture/principles/principles-are-typed.md)
- [Seven controls, seven classes](https://banes-lab.com/software-architecture/decay/seven-controls-seven-classes.md)
- [Anti-patterns](https://banes-lab.com/ontology/principles/architecture-category-anti-patterns.md)
- [Domain Architecture](https://banes-lab.com/ontology/principles/architecture-category-domain-architecture.md)
- [Core Modular Design](https://banes-lab.com/ontology/principles/architecture-category-core-modular-design.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The forces](https://banes-lab.com/ontology/schema/the-forces.md)