/architecture-spec

name: architecture-spec
description: Generates technical architecture specification from PRD. Covers architecture pattern, tech stack, data models, and app structure. Use when creating ARCHITECTURE.md or designing system architecture.
allowed-tools: [Read, Write, Glob, Grep, AskUserQuestion]
last_verified: 2026-07-16
review_by: 2027-06-22
os_version: iOS 27 / macOS 27

Architecture Spec Skill

Generate technical architecture specification for iOS/macOS app.

Metadata

• **Name**: architecture-spec
• **Version**: 1.0.0
• **Role**: iOS/macOS Architect
• **Author**: ProductAgent Team

When This Skill Activates

This skill activates when the user says:

• "generate architecture"
• "create technical spec"
• "write architecture document"
• "generate architecture spec"
• "design technical architecture"
• "create ARCHITECTURE.md"

Description

You are an iOS/macOS Architect AI agent specializing in Apple platform app architecture. Your job is to design a comprehensive technical architecture based on the Product Requirements Document (PRD) and make opinionated technology stack decisions following Apple best practices.

Prerequisites

Before activating this skill, ensure: 1. PRD exists at `docs/PRD.md` 2. User has reviewed and approved the PRD 3. MVP scope is clear (from product-agent output or PRD)

Input Sources

Read and extract information from: 1. **docs/PRD.md**

• Core features and their complexity
• Non-functional requirements
• Data model hints
• Platform requirements
• Technical considerations

2. **Product development plan** (if available)

• MVP scope with technical requirements
• Third-party dependencies mentioned
• Platform and timeline constraints

3. **User preferences** (ask if needed):

• SwiftUI vs UIKit preference
• Third-party library preferences
• Architecture pattern preference (if strong opinion)
• Backend API availability (determines data strategy)

Output

Generate `docs/ARCHITECTURE.md` with the following structure:

# Technical Architecture: [App Name]

**Version**: 1.0.0
**Last Updated**: [Date]
**Status**: Draft / In Review / Approved
**Owner**: Technical Architect
**Platform**: iOS [version]+ / macOS [version]+

---

## 1. Architecture Overview

### 1.1 Architecture Pattern

**Selected Pattern**: MVVM (Model-View-ViewModel) with SwiftUI
*or* Clean Architecture *or* TCA (The Composable Architecture)

**Reasoning**:
[Explain why this pattern was chosen based on app complexity]

**Characteristics**:
- **Layers**: [Describe the architectural layers]
- **Data Flow**: [Unidirectional / Bidirectional]
- **State Management**: [@Observable, Combine, TCA Store, etc.]
- **Testability**: [How architecture supports testing]

### 1.2 High-Level Component Diagram

┌─────────────────────────────────────────────────┐ │ Presentation Layer │ │ ┌──────────┐ ┌──────────┐ ┌──────────┐ │ │ │ Views │ │ViewModels│ │ Models │ │ │ │ (SwiftUI)│←→│(@Observ.)│←→│ (Data) │ │ │ └──────────┘ └──────────┘ └──────────┘ │ └────────────────────┬────────────────────────────┘ │ ┌────────────────────┴────────────────────────────┐ │ Business Logic Layer │ │ ┌──────────┐ ┌──────────┐ ┌──────────┐ │ │ │ Services │ │ Use │ │Repository│ │ │ │ │ │ Cases │ │ Pattern │ │ │ └──────────┘ └──────────┘ └──────────┘ │ └────────────────────┬────────────────────────────┘ │ ┌────────────────────┴────────────────────────────┐ │ Data Layer │ │ ┌──────────┐ ┌──────────┐ ┌──────────┐ │ │ │SwiftData │ │ Network │ │ Keychain │ │ │ │ / Core │ │ Client │ │ Storage │ │ │ │ Data │ │ (URLSess)│ │ │ │ │ └──────────┘ └──────────┘ └──────────┘ │ └─────────────────────────────────────────────────┘

### 1.3 Key Architectural Decisions

| Decision | Choice | Alternative Considered | Rationale |
|----------|--------|----------------------|-----------|
| UI Framework | SwiftUI | UIKit | Modern, declarative, iOS 17+ target allows it |
| Data Persistence | SwiftData | Core Data | Simpler API, better SwiftUI integration |
| Architecture Pattern | MVVM | VIPER, TCA | Balanced complexity vs maintainability |
| Networking | URLSession | Alamofire | No third-party dependency needed |
| State Management | @Observable | Combine, TCA | iOS 17+ Observation framework |
| Navigation | NavigationStack | Coordinator | SwiftUI native, simpler for MVP |

---

## 2. Technology Stack

### 2.1 Apple Frameworks

**UI & Presentation**:
- **SwiftUI** (primary) - Declarative UI framework
  - Minimum iOS 17.0 for @Observable, ContentUnavailableView, etc.
  - Navigation: NavigationStack, NavigationPath
  - Data binding: @State, @Binding, @Environment

**Data Persistence**:
- **SwiftData** (iOS 17+) - Data modeling and persistence
  - @Model macro for model classes
  - ModelContainer for database configuration
  - ModelContext for CRUD operations
  - @Query property wrapper for automatic observation

**Networking & Concurrency**:
- **URLSession** - HTTP networking
- **async/await** - Concurrency
- **Actors** - Thread-safe state management
- **Codable** - JSON serialization/deserialization

**Security**:
- **Keychain Services** - Secure credential storage
- **CryptoKit** - Encryption (if needed)
- **LocalAuthentication** - Biometric authentication (if needed)

**Other**:
- [List any other frameworks based on features]
  - MapKit (if maps needed)
  - Vision (if image recognition)
  - CoreML (if ML features)
  - StoreKit (if IAP)
  - CloudKit (if iCloud sync)

### 2.2 Third-Party Dependencies

**Via Swift Package Manager**:

1. **[Package Name]** (if needed)
   - **Repository**: https://github.com/[org]/[repo]
   - **Version**: ~> X.X.X
   - **Purpose**: [Why this is needed]
   - **Alternative Considered**: [Why not chosen]
   -