Status: Accepted
Date: 2026-09-01
Deciders: kit maintainers

0001. Hexagonal + DDD + vertical slices as the default stack

Context and Problem Statement

Waykit steers product teams (and coding agents) toward a single architectural language. Without a recorded default, agents invent ad-hoc layering or force heavy DDD onto throwaway code. We need an irreversible-enough default that still allows documented exceptions.

Decision Drivers

Shared vocabulary across languages and frameworks
Dependency direction that keeps domain logic testable without frameworks
Feature delivery that avoids shotgun surgery across technical layers
Escape hatch so small/CRUD/spike work is not over-architected

Considered Options

Option A: Mandate hexagonal + DDD + vertical slices for all code always
Option B: Soft guidance only; no default stack
Option C: Default stack for product codebases, with explicit applicability and ADR opt-out

Decision Outcome

Chosen option: "Option C", because a strong default improves agent routing and review quality, while CODING_PHILOSOPHY.md applicability criteria prevent force-fitting the full stack onto scripts and short-lived CRUD.

Consequences

Good, because skills, evals, and audits share one expected shape
Bad, because newcomers may over-apply ports/aggregates until they read applicability
Follow-up: keep ADRs sparse; use opt-out notes for one-off exceptions