Architecture Shared (all languages) active any

Boundary data is simple, isolated, and framework-free

clean-arch-004

Intent

Data crossing an architectural boundary should be shaped for the inner side of that boundary, not drag framework, transport, or storage types inward.

Applicability

Applies when the diff changes request/response models, signatures, presenter models, gateway results, or other cross-boundary data.

What to inspect

Changed parameter and return types, DTOs, request models, and mapper boundaries.

Pass criteria

Boundary methods use simple DTOs, commands, queries, or records that are free of outer-layer framework dependencies.

Fail criteria

The diff passes HttpRequest, ORM entities, generated transport models, or similar outer types into an inner layer.

Do not flag

Outer-layer types that stay at the edge and are immediately mapped.

Confidence guidance

HIGH when the signature directly exposes an outer type. MEDIUM when the crossing is inferred from layout. LOW when the boundary itself is unclear.

Remediation

Introduce inward-facing boundary models and map at the adapter edge.

Pass example

record CreateOrderCommand(String customerId, List<String> items) {}

Fail example

CreateOrderResponse handle(HttpServletRequest request)