software-architecture

SKILL.md

Software Architecture Development Skill

This skill provides guidance for quality focused software development and architecture. It is based on Clean Architecture and Domain Driven Design principles.

Code Style Rules

General Principles

Early return pattern: Always use early returns when possible, over nested conditions for better readability

Avoid code duplication through creation of reusable functions and modules

Decompose long (more than 80 lines of code) components and functions into multiple smaller components and functions. If they cannot be used anywhere else, keep it in the same file. But if file longer than 200 lines of code, it should be split into multiple files.

Use arrow functions instead of function declarations when possible

Best Practices

Library-First Approach

ALWAYS search for existing solutions before writing custom code

Check npm for existing libraries that solve the problem

Evaluate existing services/SaaS solutions

Consider third-party APIs for common functionality

Use libraries instead of writing your own utils or helpers. For example, use cockatiel instead of writing your own retry logic.

When custom code IS justified:

Specific business logic unique to the domain

Performance-critical paths with special requirements

When external dependencies would be overkill

Security-sensitive code requiring full control

When existing solutions don't meet requirements after thorough evaluation

Architecture and Design

Clean Architecture & DDD Principles:

Follow domain-driven design and ubiquitous language

Separate domain entities from infrastructure concerns

Keep business logic independent of frameworks

Define use cases clearly and keep them isolated

Naming Conventions:

AVOID generic names: utils, helpers, common, shared

USE domain-specific names: OrderCalculator, UserAuthenticator, InvoiceGenerator

Follow bounded context naming patterns

Each module should have a single, clear purpose

Separation of Concerns:

Do NOT mix business logic with UI components

Keep database queries out of controllers

Maintain clear boundaries between contexts

Ensure proper separation of responsibilities

Anti-Patterns to Avoid

NIH (Not Invented Here) Syndrome:

Don't build custom auth when Auth0/Supabase exists

Don't write custom state management instead of using Redux/Zustand

Don't create custom form validation instead of using established libraries

Poor Architectural Choices:

Mixing business logic with UI components

Database queries directly in controllers

Lack of clear separation of concerns

Generic Naming Anti-Patterns:

utils.js with 50 unrelated functions

helpers/misc.js as a dumping ground

common/shared.js with unclear purpose

Remember: Every line of custom code is a liability that needs maintenance, testing, and documentation

Code Quality

Proper error handling with typed catch blocks

Break down complex logic into smaller, reusable functions

Avoid deep nesting (max 3 levels)

Keep functions focused and under 50 lines when possible

Keep files focused and under 200 lines of code when possible

When to Use

This skill is applicable to execute the workflow or actions described in the overview.

Limitations

Use this skill only when the task clearly matches the scope described above.

Do not treat the output as a substitute for environment-specific validation, testing, or expert review.

Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.