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Design, implement, and refactor Ports & Adapters systems with clear domain boundaries, dependency inversion, and testable use-case orchestration across TypeScript, Java, Kotlin, and Go services.
Instinct-based learning system that observes sessions via hooks, creates atomic instincts with confidence scoring, and evolves them into skills/commands/agents. v2.1 adds project-scoped instincts to prevent cross-project contamination.
Orchestrate building a brand-new feature end to end — research, plan, TDD implementation, review, and gated commit — by delegating each phase to the matching ECC agent. Use when adding a capability that does not exist yet.
Orchestrate bootstrapping a working MVP from a design or spec document — ingest the doc, plan thin vertical slices, scaffold the first end-to-end slice, then TDD-implement, review, and gated commit. Use to turn an SDD/PRD into a running starting point.
Orchestrate altering an existing, working feature to new desired behavior — update its tests to the new spec, change the implementation to match, review, and gated commit. Use when behavior is not broken but should be different.
Orchestrate fixing a bug — reproduce it as a failing regression test, fix to green, review, and gated commit — by delegating each phase to the matching ECC agent. Use when existing behavior is broken or wrong.
Shared orchestration engine for the orch-* skill family. Defines the gated Research-Plan-TDD-Review-Commit pipeline, the size classifier, the agent map, and the two human gates that the orch-* operation skills delegate to. Not usually invoked directly.
| name | hexagonal-architecture |
| description | Design, implement, and refactor Ports & Adapters systems with clear domain boundaries, dependency inversion, and testable use-case orchestration across TypeScript, Java, Kotlin, and Go services. |
| origin | ECC |
Hexagonal architecture (Ports and Adapters) keeps business logic independent from frameworks, transport, and persistence details. The core app depends on abstract ports, and adapters implement those ports at the edges.
Use this skill when the request involves boundaries, domain-centric design, refactoring tightly coupled services, or decoupling application logic from specific libraries.
Outbound port interfaces usually live in the application layer (or in domain only when the abstraction is truly domain-level), while infrastructure adapters implement them.
Dependency direction is always inward:
Define a single use case with a clear input and output DTO. Keep transport details (Express req, GraphQL context, job payload wrappers) outside this boundary.
Identify every side effect as a port:
UserRepositoryPort)BillingGatewayPort)LoggerPort, ClockPort)Ports should model capabilities, not technologies.
Use case class/function receives ports via constructor/arguments. It validates application-level invariants, coordinates domain rules, and returns plain data structures.
Instantiate adapters, then inject them into use cases. Keep this wiring centralized to avoid hidden service-locator behavior.
flowchart LR
Client["Client (HTTP/CLI/Worker)"] --> InboundAdapter["Inbound Adapter"]
InboundAdapter -->|"calls"| UseCase["UseCase (Application Layer)"]
UseCase -->|"uses"| OutboundPort["OutboundPort (Interface)"]
OutboundAdapter["Outbound Adapter"] -->|"implements"| OutboundPort
OutboundAdapter --> ExternalSystem["DB/API/Queue"]
UseCase --> DomainModel["DomainModel"]
Use feature-first organization with explicit boundaries:
src/
features/
orders/
domain/
Order.ts
OrderPolicy.ts
application/
ports/
inbound/
CreateOrder.ts
outbound/
OrderRepositoryPort.ts
PaymentGatewayPort.ts
use-cases/
CreateOrderUseCase.ts
adapters/
inbound/
http/
createOrderRoute.ts
outbound/
postgres/
PostgresOrderRepository.ts
stripe/
StripePaymentGateway.ts
composition/
ordersContainer.ts
export interface OrderRepositoryPort {
save(order: Order): Promise<void>;
findById(orderId: string): Promise<Order | null>;
}
export interface PaymentGatewayPort {
authorize(input: { orderId: string; amountCents: number }): Promise<{ authorizationId: string }>;
}
type CreateOrderInput = {
orderId: string;
amountCents: number;
};
type CreateOrderOutput = {
orderId: string;
authorizationId: string;
};
export class CreateOrderUseCase {
constructor(
private readonly orderRepository: OrderRepositoryPort,
private readonly paymentGateway: PaymentGatewayPort
) {}
async execute(input: CreateOrderInput): Promise<CreateOrderOutput> {
const order = Order.create({ id: input.orderId, amountCents: input.amountCents });
const auth = await this.paymentGateway.authorize({
orderId: order.id,
amountCents: order.amountCents,
});
// markAuthorized returns a new Order instance; it does not mutate in place.
const authorizedOrder = order.markAuthorized(auth.authorizationId);
await this.orderRepository.save(authorizedOrder);
return {
orderId: order.id,
authorizationId: auth.authorizationId,
};
}
}
export class PostgresOrderRepository implements OrderRepositoryPort {
constructor(private readonly db: SqlClient) {}
async save(order: Order): Promise<void> {
await this.db.query(
"insert into orders (id, amount_cents, status, authorization_id) values ($1, $2, $3, $4)",
[order.id, order.amountCents, order.status, order.authorizationId]
);
}
async findById(orderId: string): Promise<Order | null> {
const row = await this.db.oneOrNone("select * from orders where id = $1", [orderId]);
return row ? Order.rehydrate(row) : null;
}
}
export const buildCreateOrderUseCase = (deps: { db: SqlClient; stripe: StripeClient }) => {
const orderRepository = new PostgresOrderRepository(deps.db);
const paymentGateway = new StripePaymentGateway(deps.stripe);
return new CreateOrderUseCase(orderRepository, paymentGateway);
};
Use the same boundary rules across ecosystems; only syntax and wiring style change.
application/ports/* as interfaces/types.adapters/inbound/*, adapters/outbound/*.domain, application.port.in, application.port.out, application.usecase, adapter.in, adapter.out.application.port.*.@Service is optional, not required).domain, application.port, application.usecase, adapter).internal/<feature>/domain, application, ports, adapters/inbound, adapters/outbound.New... constructors.cmd/<app>/main.go (or dedicated wiring package), keep constructors explicit.req, res, or queue metadata.