High Cohesion / Low Coupling (Review Skill)

Use when

• A change touches multiple folders/layers/capabilities.

• You’re tempted to import a file from another capability.

• “Shared” is being considered for convenience.

Checklist (fast)

• Ownership: which capability/bounded context owns the rule/data?

• Cohesion: is the logic colocated with its change reason?

• Coupling: are dependencies narrow (ports/events) rather than concrete imports?

• Public surface: can exports be reduced to the minimal stable interface?

• Import hygiene: any deep imports into another capability/layer?

• Promotion: does it truly qualify for shared (2+ contexts, no business policy)?

Smallest fixes (preferred order)

• Move code to the owner (increase cohesion).

• Introduce/adjust a port or event (reduce coupling).

• Narrow exports / add an explicit entry point (stabilize interface).

• Only then consider shared (if it meets promotion rules).

References

• .github/instructions/06-cohesion-coupling-copilot-instructions.md

• .github/instructions/05-design-principles-copilot-instructions.md

• scripts/dependency-cruiser.js