# Layer Spine Precedence

> A mechanism that breaks an irreducible tie between two roles in favor of the one nearer the domain on the layer spine.

Record: `architecture:layer-spine-precedence`
Kind: mechanism
Layer: [Structural Core](https://banes-lab.com/records/layer/structural-core.md)
Severity: contextual
Scope: file
Canonical: https://banes-lab.com/ontology#architecture-layer-spine-precedence

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Narrowest Concern](https://banes-lab.com/records/architecture/narrowest-concern.md) and before [Agnostic-First Vocabulary](https://banes-lab.com/records/architecture/agnostic-first-vocabulary.md).

## Repair

- Refactored by: Apply the Domain-Ward Tie-Break
- Detected by: an irreducible two-concern overlap resolved by preference rather than by layer
- Violated by: reading the spine as a dependency-direction rule rather than a classification tie-break
- Measured by: unresolved overlap count
- Enforced by: classification review

## Requires

- [Layer Spine](https://banes-lab.com/records/lexicon/layer-spine.md)

## Reinforces

- [Narrowest Concern](https://banes-lab.com/records/architecture/narrowest-concern.md)

## Enables

- [Placement Predictability](https://banes-lab.com/records/lexicon/placement-predictability.md)

## Conflicts with

- [Multi-Role File](https://banes-lab.com/records/lexicon/multi-role-file.md)

## Severity

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

## Category

- [Taxonomy / Classification / Naming](https://banes-lab.com/records/architecture-category/taxonomy-classification-naming.md)

## Linked from

- [The layer spine](https://banes-lab.com/software-architecture/model/the-layer-spine.md)
- [Taxonomy / Classification / Naming](https://banes-lab.com/ontology/principles/architecture-category-taxonomy-classification-naming.md)
- [Taxonomy / Classification / Naming](https://banes-lab.com/ontology/lexicon/lexicon-category-taxonomy-classification-naming.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)