# Code Structure

Use when multiple workflows duplicate the same operational logic, when deciding what...

- Repository: https://github.com/michaelshimeles/rstack (1423 stars)
- Category: Engineering
- License: see repository
- Last updated: 2026-10-26
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add michaelshimeles/rstack --skill code-structure -g -a claude-code -y`
Codex: `npx skills add michaelshimeles/rstack --skill code-structure -g -a codex -y`
Cursor: `npx skills add michaelshimeles/rstack --skill code-structure -g -a cursor -y`
Gemini CLI: `npx skills add michaelshimeles/rstack --skill code-structure -g -a gemini-cli -y`

## Description

Use when multiple workflows duplicate the same operational logic, when deciding what belongs in actions vs shared services, or when refactoring repeated operational blocks across domain flows. Use when adding new features that share mechanics with existing ones.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Service Layer Architecture

## Overview

This collection prefers a two-layer separation: actions orchestrate domain
rules, while services implement reusable operations. Use it where the project
has no established convention. Preserve existing domain services, repositories,
transaction boundaries, and framework patterns when they already fit the task.

This prevents duplicated code, inconsistent behavior, and bugs fixed in one path but not others.

## When to Use

- Multiple callers need the same low-level operation (sandbox creation, email sending, payment processing)
- You're copy-pasting operational logic between action files
- A bug fix in one workflow doesn't propagate to others doing the same thing
- Adding a new feature that shares mechanics with existing flows

Avoid extraction that adds indirection without a concrete benefit. Repetition
is a useful signal, but a single caller can justify a boundary for testing,
provider isolation, transactions, or complex logic.

## Core Pattern

```
Orchestration Layer (Actions)          Service Layer (Shared Mechanics)
├── owns business rules                ├── owns reusable operations
├── owns state transitions             ├── owns provider/SDK interactions
├── owns auth/ownership checks         ├── owns command execution details
├── owns failure classification        ├── owns health checks / readiness
├── owns retries / user-facing errors  └── returns structured results
└── calls service functions
```

**Rule of thumb:**
- "What this product flow means" → keep in actions
- "How to do this operation reliably" → move to service layer

## Quick Reference

The rest: https://github.com/michaelshimeles/rstack/blob/HEAD/code-structure/SKILL.md