Layers and Namespace Patterns

Layers are named architecture surfaces used by contracts.

layers:
  application:
    namespace: MyApp.Application
  domain:
    namespace: MyApp.Domain

Contract rules reference layer keys such as application and domain.

Literal namespace prefixes

A literal namespace value matches the exact namespace and child namespaces:

layers:
  domain:
    namespace: MyApp.Domain

This matches MyApp.Domain, MyApp.Domain.Models, and deeper descendants. It does not match unrelated prefixes such as MyApp.DomainLegacy.

Constrained namespace globs

namespace supports a constrained * wildcard when it occupies a complete namespace segment:

layers:
  feature_modules:
    namespace: MyApp.Features.*

Rules:

• * matches exactly one namespace segment.
• Descendants under the resolved prefix also match.
• * must be a full segment.
• Multi-segment wildcards, partial-segment wildcards, character classes, and regular-expression syntax are not supported.
• Leading wildcard patterns are not supported.

Examples:

Pattern	Namespace	Matches?
MyApp.Features.*	MyApp.Features.Audio	yes
MyApp.Features.*	MyApp.Features.Audio.Player	yes
MyApp.Features.*	MyApp.Features	no
MyApp.Features.*	MyApp.Other.Audio	no

Namespace suffix

Use namespace_suffix to model conventions such as Contracts, Models, or Api slices:

layers:
  feature_contracts:
    namespace: MyApp.Features.*
    namespace_suffix: Contracts

With glob patterns, the suffix is position-fixed immediately after the resolved wildcard segment.

Matches:

• MyApp.Features.Audio.Contracts
• MyApp.Features.Audio.Contracts.Dto

Does not match:

• MyApp.Features.Audio.Internal.Contracts

External layers

When a layer references namespaces whose assemblies may not be present in the scan environment, set external: true:

layers:
  unity_engine:
    namespace: UnityEngine
    external: true

External layers suppress empty-layer configuration diagnostics, but they can still be used in dependency, allow-only, layer, cycle, independence, and protected-surface contracts.

For new vendor/framework leakage rules, prefer external_dependencies and strict_external / audit_external contracts.

Tips

• Prefer narrow concrete layers for important rules.
• Use glob layers for repeated sibling layouts where hand-listing every namespace would be brittle.
• Do not mix broad aggregate layers and overlapping child layers in the same ordered layer contract unless that overlap is deliberate and documented.