void-dependency-direction

Define a port interface in the consuming package, then wire the adapter at the app level. For example, billing declares a BillingPorts interface and apps/web injects the @repo/auth-backed implementation, so packages never import each other directly.

This Skill enforces that @repo/* packages may only import @repo/core, which ships leaf primitives like logger, env, errors, and Result. Apps may import any @repo/* package, and all composition happens at the app level.

Packages should declare their own narrowed type projections rather than importing types from sibling packages, since type imports still create coupling. If a shape is genuinely shared, factor it into @repo/core/types.

The hook blocks Edit/Write operations that introduce imports violating the @repo/* direction rule, such as one feature package importing another. You can override with a // allow-boundary: comment, but the recommended fix is refactoring to ports and adapters.

Exceptions are rare; most needs dissolve once a port is defined. If you still believe one is required, write an ADR documenting the exception and its reversal cost before tagging the import with an allow comment.