SKILL: backend-architecture

Purpose

Design backend systems with clear boundaries: API contracts, services, persistence, observability, and security controls.

When to Use

• Building a new backend or major subsystem.
• Introducing a new API surface (REST/WebSocket).
• You need a concrete module/service layout and DB model.

Inputs

• requirements (required, string|object): endpoints, behaviors, SLAs, compliance needs.
• constraints (optional, string[]): security, latency, cost, runtime, stack limits.
• data_entities (optional, string[]): core domain objects.
• integration_points (optional, string[]): external services/APIs.