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)

1. Ownership: which capability/bounded context owns the rule/data?
2. Cohesion: is the logic colocated with its change reason?
3. Coupling: are dependencies narrow (ports/events) rather than concrete imports?
4. Public surface: can exports be reduced to the minimal stable interface?
5. Import hygiene: any deep imports into another capability/layer?
6. 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