Architecture Review

Architecture and design pattern validation for ultrawork planning and verification phases.

What This Skill Provides

Structured approach to evaluating:

• Component boundaries and separation of concerns
• Modularity and coupling
• Design patterns and architectural principles
• Scalability and maintainability
• API design and interfaces

When to Use This Skill

During PLANNING phase:

• Reviewing planner's task decomposition
• Validating design documents
• Assessing technical approach
• Identifying architectural risks

During VERIFICATION phase:

• Ensuring implementation matches design
• Checking component boundaries
• Validating separation of concerns
• Reviewing integration points

Core Principles

1. Separation of Concerns (SoC)

Checklist:

[ ] Business logic separated from presentation
[ ] Data access layer isolated
[ ] Authentication/authorization in dedicated modules
[ ] Configuration separate from code
[ ] API routes separate from business logic
[ ] Validation logic reusable across layers
[ ] Error handling centralized
[ ] Logging abstracted

Red Flags:

• Business logic in React components
• Database queries in route handlers
• Authentication mixed with business logic
• Configuration hardcoded in multiple files

Examples:

// ❌ Bad: Mixed concerns
app.post('/api/users', async (req, res) => {
  // Authentication + validation + business logic + DB access in one place
  if (!req.headers.authorization) return res.status(401).json({ error: 'Unauthorized' });
  if (!req.body.email) return res.status(400).json({ error: 'Email required' });
  const user = await db.users.create(req.body);
  res.json(user);
});

// ✅ Good: Separated concerns
app.post('/api/users',
  authenticate,           // Auth middleware
  validateCreateUser,     // Validation middleware
  createUserHandler       // Route handler delegates to service
);

async function createUserHandler(req, res) {
  const user = await userService.createUser(req.body); // Business logic in service
  res.json(user);
}

2. Component Boundaries

Checklist:

[ ] Components have clear, single responsibilities
[ ] Component interfaces are well-defined
[ ] Dependencies flow in one direction (no circular deps)
[ ] Components are independently testable
[ ] Public APIs are minimal (principle of least exposure)
[ ] Internal implementation details are hidden
[ ] Components can be replaced without breaking others

Red Flags:

• Circular dependencies (A imports B, B imports A)
• God objects (classes with 10+ responsibilities)
• Tight coupling (changes in A always require changes in B)
• Leaky abstractions (internal details exposed)

Dependency Flow:

Presentation → Business Logic → Data Access → Database
     ↓              ↓                ↓
   UI Layer    Service Layer    Repository Layer

NEVER: Data Access → Presentation (wrong direction!)

3. Modularity and Coupling

Checklist:

[ ] Modules are cohesive (related functionality grouped)
[ ] Low coupling between modules
[ ] Shared code in libraries/utilities
[ ] Feature folders group related files
[ ] Module exports are explicit and minimal
[ ] Dependencies are injected (not hardcoded)
[ ] Configuration passed from outside

Cohesion vs Coupling:

Good Modularity	Bad Modularity
High cohesion (related code together)	Low cohesion (unrelated code mixed)
Low coupling (minimal dependencies)	High coupling (everything depends on everything)
Clear interfaces	Implicit contracts
Dependency injection	Hardcoded dependencies

Examples:

// ❌ Bad: High coupling, hardcoded dependencies
class UserService {
  constructor() {
    this.db = new PostgresDB(); // Hardcoded!
    this.logger = console;       // Hardcoded!
  }
}

// ✅ Good: Low coupling, dependency injection
class UserService {
  constructor(database, logger) {
    this.db = database;
    this.logger = logger;
  }
}

// Usage: dependencies injected
const userService = new UserService(
  new PostgresDB(config.db),
  new Logger(config.logging)
);

4. Design Patterns

Checklist:

[ ] Patterns used appropriately (not overengineered)
[ ] Consistent patterns across codebase
[ ] Standard patterns preferred over custom solutions
[ ] Patterns documented in code

Common Patterns:

Pattern	Use When	Example
Repository	Data access abstraction	userRepository.findById(id)
Service	Business logic encapsulation	orderService.placeOrder()
Factory	Object creation complexity	PaymentFactory.create(type)
Strategy	Swappable algorithms	ShippingStrategy.calculate()
Middleware	Request/response processing	Express middleware
Observer	Event-driven updates	Event emitters, pub/sub

Red Flags:

• Patterns used incorrectly
• Over-abstraction (patterns for simple problems)
• Mixing patterns inconsistently
• Custom patterns when standard ones exist

5. API Design

Checklist:

[ ] RESTful conventions followed (GET/POST/PUT/DELETE)
[ ] Consistent URL structure
[ ] Proper HTTP status codes
[ ] Versioning strategy defined
[ ] Request/response schemas documented
[ ] Error responses are consistent
[ ] Pagination for collections
[ ] Filtering and sorting supported where needed

REST Conventions:

HTTP Method	Purpose	Idempotent?
GET	Retrieve resource	Yes
POST	Create resource	No
PUT	Update/replace resource	Yes
PATCH	Partial update	No
DELETE	Remove resource	Yes

Examples:

// ❌ Bad: Inconsistent, non-RESTful
POST /getUser
POST /deleteUser
GET /updateUser?id=123&name=John

// ✅ Good: RESTful, consistent
GET    /api/users/:id      (retrieve)
POST   /api/users          (create)
PUT    /api/users/:id      (update)
DELETE /api/users/:id      (delete)

6. Scalability Considerations

Checklist:

[ ] Stateless design (no server-side state)
[ ] Database queries optimized (indexes, joins)
[ ] Caching strategy defined
[ ] Async operations for I/O
[ ] Rate limiting implemented
[ ] Pagination on large datasets
[ ] Background jobs for heavy processing
[ ] CDN for static assets

Red Flags:

• Storing state in memory (server-side sessions)
• Synchronous blocking operations
• No caching for expensive operations
• Loading entire tables
• Missing indexes on query columns

Layer Architecture Patterns

3-Tier Architecture

┌─────────────────────┐
│  Presentation Layer │  (UI, API routes)
└──────────┬──────────┘
           │
┌──────────▼──────────┐
│   Business Layer    │  (Services, logic)
└──────────┬──────────┘
           │
┌──────────▼──────────┐
│    Data Layer       │  (Repositories, DB)
└─────────────────────┘

Rules:

• Upper layers can call lower layers
• Lower layers CANNOT call upper layers
• Layers communicate via interfaces

Feature-Based Structure

src/
├── features/
│   ├── auth/
│   │   ├── auth.service.ts
│   │   ├── auth.controller.ts
│   │   ├── auth.repository.ts
│   │   └── auth.test.ts
│   ├── users/
│   │   ├── user.service.ts
│   │   ├── user.controller.ts
│   │   └── user.repository.ts
├── shared/
│   ├── utils/
│   ├── middleware/
│   └── types/

Benefits:

• Related code together
• Easy to find files
• Scalable structure
• Clear ownership

Review Process

Step 1: High-Level Assessment

Answer:

• What is the overall architecture pattern?
• Are responsibilities clearly separated?
• Is the dependency flow correct?
• Can components be tested independently?

Step 2: Component Analysis

For each component:

• What is its single responsibility?
• What are its dependencies?
• Is its interface minimal and clear?
• Is it properly abstracted?

Step 3: Integration Review

Check:

• How do components communicate?
• Are interfaces well-defined?
• Is error handling consistent?
• Are transactions handled correctly?

Step 4: Design Document Review

Verify:

• Design rationale is documented
• Trade-offs are explained
• Alternative approaches considered
• Scalability addressed
• Security considered

Architecture Smells

Smell	Description	Fix
Big Ball of Mud	No clear structure	Refactor into layers
God Object	Class does everything	Split into focused classes
Spaghetti Code	Tangled dependencies	Extract interfaces, dependency injection
Circular Dependencies	A depends on B, B depends on A	Introduce abstraction layer
Tight Coupling	Changes cascade everywhere	Loose coupling via interfaces
Anemic Domain	Logic scattered, not in models	Move logic to domain models

Design Principles (SOLID)

S - Single Responsibility Principle

Each class/module has one reason to change.

// ❌ Bad: Multiple responsibilities
class UserManager {
  createUser() { /* ... */ }
  sendEmail() { /* ... */ }
  logActivity() { /* ... */ }
}

// ✅ Good: Single responsibility
class UserService {
  createUser() { /* ... */ }
}
class EmailService {
  sendEmail() { /* ... */ }
}

O - Open/Closed Principle

Open for extension, closed for modification.

// ❌ Bad: Must modify for new types
function calculateShipping(order) {
  if (order.type === 'standard') return 5;
  if (order.type === 'express') return 15;
  // Must modify function for new types
}

// ✅ Good: Extend via strategy pattern
class StandardShipping {
  calculate() { return 5; }
}
class ExpressShipping {
  calculate() { return 15; }
}

L - Liskov Substitution Principle

Subtypes must be substitutable for base types.

I - Interface Segregation Principle

Many small interfaces better than one large interface.

D - Dependency Inversion Principle

Depend on abstractions, not concrete implementations.

Evidence Collection

When reviewing architecture:

# Add architecture assessment to evidence
bun "{SCRIPTS_PATH}/task-update.js" --session ${CLAUDE_SESSION_ID} --id verify \
  --add-evidence "Architecture Review: PASS" \
  --add-evidence "- Clear separation of concerns" \
  --add-evidence "- Proper component boundaries" \
  --add-evidence "- No circular dependencies" \
  --add-evidence "- RESTful API design"

Common Issues and Fixes

Issue	Impact	Fix
Business logic in controllers	Hard to test, hard to reuse	Extract to service layer
No repository layer	Direct DB coupling	Introduce repository pattern
Circular dependencies	Build errors, tight coupling	Introduce abstraction layer
God classes	Unmaintainable	Split by responsibility
No interfaces	Tight coupling	Define clear interfaces
Mixed layers	Confusion, bugs	Enforce layer boundaries

Integration with Ultrawork

During PLANNING Phase

# Review design document
Read("$SESSION_DIR/docs/plans/design.md")

# Check task decomposition aligns with architecture
bun "{SCRIPTS_PATH}/task-list.js" --session ${CLAUDE_SESSION_ID}

# Validate component boundaries in plan

During VERIFICATION Phase

# Check implementation matches design
git diff

# Verify component boundaries maintained
# Check for circular dependencies
# Validate layer separation

Quick Reference

Must-have architecture standards:

• Clear layer separation (presentation/business/data)
• Single responsibility per component
• Dependency injection for flexibility
• RESTful API conventions
• No circular dependencies

Red flags:

• Business logic in presentation layer
• Circular dependencies
• God objects/classes
• Tight coupling
• Inconsistent patterns