software-design-principles

name	software-design-principles
description	Reference guide for software design properties and principles: SOLID, GRASP, Law of Demeter, cohesion, coupling, information hiding, conceptual integrity, modularisation, module-level principles (REP/CCP/CRP/ADP/SDP/SAP), composition over inheritance, and immutability. ALWAYS activate this skill when: performing code reviews, designing classes or modules, evaluating dependencies or abstractions, discussing SOLID principles, analysing coupling or cohesion, reviewing inheritance hierarchies, making architectural decisions about package structure, or any time the conversation involves design quality, code maintainability, or software design principles.
metadata	{"author":"wesleyegberto","version":"1.0.0","scope":"architecture"}

Software Design Properties and Principles

This skill is a reference companion for code review and software design sessions. Each concept lives in its own reference file — read only the file(s) relevant to the current task.

Reference Files

File	Contents
references/design-properties.md	Cohesion, Coupling, Information Hiding, Conceptual Integrity
references/solid.md	SRP, OCP, LSP, ISP, DIP — with nuances and critical counterpoints
references/grasp-demeter.md	GRASP patterns, Law of Demeter, Tell-Don't-Ask
references/modularization.md	Modularisation, REP/CCP/CRP, ADP/SDP/SAP, metrics
references/composition-immutability.md	Prefer Composition over Inheritance, Immutability rules
references/simplicity.md	Causes of complexity, abstraction leaks, scale, model/reality gaps
references/error-handling.md	Error types, when/where to handle, flow control, checked exceptions
references/code-review-checklist.md	Unified checklist + quick red-flag table for reviews

When to Read Each File

During a code review: Start with code-review-checklist.md for a structured walkthrough, then open the specific reference file for deeper context on any flagged issue.

During software design:

• Deciding class responsibilities → design-properties.md (cohesion, coupling)
• Designing interfaces or inheritance → solid.md + composition-immutability.md
• Assigning responsibilities to objects → grasp-demeter.md
• Structuring packages or modules → modularization.md
• Evaluating complexity or discussing simplicity trade-offs → simplicity.md
• Reviewing error handling, exception design, or propagation strategy → error-handling.md

Core Principle Map

Goal                         Practice
────────────────────────────────────────────────────────────
High Cohesion           ←─   SRP, ISP, CCP, GRASP High Cohesion
Low Coupling            ←─   DIP, Law of Demeter, Composition, SDP
Information Hiding      ←─   Law of Demeter, Private fields, API Module
Extensibility           ←─   OCP, LSP, Protected Variations
Module Stability        ←─   ADP, SDP, SAP
Reusability             ←─   REP, CRP, Separate Abstractions
Thread Safety           ←─   Immutability

Property → Principle Quick Lookup

Property	Principles
Cohesion	SRP, ISP, CCP
Coupling	DIP, Law of Demeter, Composition > Inheritance, SDP
Information Hiding	Law of Demeter, CCP, Separate Abstractions
Extensibility	OCP, LSP, Protected Variations (GRASP)
Module stability	ADP (no cycles), SDP (stable direction), SAP (abstract = stable)