architecture-patterns

Architecture Patterns - Backend Architecture Agent

Skill Overview

Architecture Patterns is an agent skill focused on backend architecture design. It helps developers master proven architecture patterns such as Clean Architecture, Hexagonal Architecture, and Domain-Driven Design (DDD) to build maintainable, testable, and scalable backend systems.

Applicable Scenarios

1. Designing a new backend system from scratch

When you need to design a brand-new backend architecture for a complex business domain, this skill can help you choose the appropriate architecture pattern, define clear module boundaries and dependency rules, and avoid the high costs of later refactoring.

2. Refactoring a monolithic application

When facing an increasingly complex and hard-to-maintain monolith, this skill provides concrete steps to migrate from a tightly coupled architecture to a loosely coupled one, including how to split domain boundaries, establish interface abstractions, and validate the effectiveness of architectural improvements.

3. Establishing team architecture standards

When a team needs unified architecture guidelines, this skill helps create a pattern selection guide appropriate for the business complexity, code organization principles, and a checklist of best practices to improve team collaboration efficiency and code quality.

Core Features

Architecture pattern selection and guidance

Recommend the best-matching architecture pattern (Clean Architecture, Hexagonal Architecture, or DDD) based on business complexity, team size, and scalability goals, and provide each pattern’s core principles, applicable scenarios, and implementation highlights.

Domain boundary and dependency rules definition

Assist in identifying core domains, subdomains, and the ubiquitous language; define clear module boundaries and interface contracts; establish dependency inversion rules to ensure business logic is decoupled from infrastructure implementations, improving code testability and replaceability.

Migration path and validation checklist

Provide a step-by-step guide to migrate from the existing architecture to the target architecture, including the order of code structure adjustments, testing strategies, and checkpoints for validating architectural health, ensuring the refactor process is controlled and rollable.

Frequently Asked Questions

What is the difference between Clean Architecture and Hexagonal Architecture?

Their core ideas are the same: both emphasize dependency inversion and decoupling business logic from infrastructure. Clean Architecture, proposed by Uncle Bob, emphasizes concentric layered rings and inward-directed dependencies; Hexagonal Architecture (Ports and Adapters), proposed by Alistair Cockburn, emphasizes isolating the application core through ports and adapters. In practice, choosing one over the other is often a matter of team preference and expression style.

When should I use Domain-Driven Design (DDD)?

DDD is best suited for systems with complex business logic that require long-term team collaboration. If the business rules are simple and mostly CRUD, the extra complexity of DDD may not be worth it. Signals that DDD might be appropriate include: multiple domain experts need to communicate, business terminology is frequently confused, similar business logic is scattered across the codebase, and new feature development requires understanding many implicit rules.

Will migrating from a traditional architecture to Clean Architecture significantly increase development costs?

There will be an initial learning curve and architectural adjustment costs, but in the long run it can reduce maintenance costs and the bug rate. It’s recommended to migrate incrementally: start using the new pattern in new modules to build team experience and templates; then gradually refactor core domains, adding test protection after each refactor. Do not attempt to rewrite the entire system at once.