What It Does When you work on a Spring Boot project with Claude Code, this plugin enforces: Hexagonal architecture with clear domain/application/infrastructure separation Feature-oriented package structure instead of framework-driven sprawl Explicit layer rules — domain never depends on Spring, JPA entities stay in infrastructure, controllers delegate to use cases API design standards — OpenAPI, consistent error contracts, validation at all levels Security baseline — deny-by-default, least privilege, protected actuators Testing strategy — unit, integration, contract, and non-functional tests with Testcontainers Observability — structured logging, trace IDs, metrics, health endpoints Database discipline — Flyway migrations, no Hibernate DDL in production The skill automatically detects whether your project is a modular monolith or microservices system and loads the appropriate guide.