designing-architecture

Designs software architecture and selects appropriate patterns for projects. Use when designing systems, choosing architecture patterns, structuring projects, making technical decisions, or when asked about microservices, monoliths, or architectural approaches.

Quality

73%

Does it follow best practices?

Run evals on this skill

Adds up to 20 points to the overall score

View guide

Securityby

Passed

No findings from the security scan

Fix and improve this skill with Tessl

tessl review fix ./skills/designing-architecture/SKILL.md

Designing Architecture

When to Load

Trigger: System design, module structure, new project scaffolding, choosing architecture patterns
Skip: Simple bug fixes or minor code changes that don't affect architecture

Architecture Decision Workflow

Copy this checklist and track progress:

Architecture Design Progress:
- [ ] Step 1: Understand requirements and constraints
- [ ] Step 2: Assess project size and team capabilities
- [ ] Step 3: Select architecture pattern
- [ ] Step 4: Define directory structure
- [ ] Step 5: Document trade-offs and decision
- [ ] Step 6: Validate against decision framework

Pattern Selection Guide

By Project Size

Size	Recommended Pattern
Small (<10K LOC)	Simple MVC/Layered
Medium (10K-100K)	Clean Architecture
Large (>100K)	Modular Monolith or Microservices

By Team Size

Team	Recommended
1-3 devs	Monolith with clear modules
4-10 devs	Modular Monolith
10+ devs	Microservices (if justified)

Common Patterns

1. Layered Architecture

┌─────────────────────────────┐
│       Presentation          │  ← UI, API Controllers
├─────────────────────────────┤
│       Application           │  ← Use Cases, Services
├─────────────────────────────┤
│         Domain              │  ← Business Logic, Entities
├─────────────────────────────┤
│      Infrastructure         │  ← Database, External APIs
└─────────────────────────────┘

Use when: Simple CRUD apps, small teams, quick prototypes

2. Clean Architecture

┌─────────────────────────────────────┐
│            Frameworks & Drivers      │
│  ┌─────────────────────────────┐    │
│  │     Interface Adapters       │    │
│  │  ┌─────────────────────┐    │    │
│  │  │   Application       │    │    │
│  │  │  ┌─────────────┐    │    │    │
│  │  │  │   Domain    │    │    │    │
│  │  │  └─────────────┘    │    │    │
│  │  └─────────────────────┘    │    │
│  └─────────────────────────────┘    │
└─────────────────────────────────────┘

Use when: Complex business logic, long-lived projects, testability is key

3. Hexagonal (Ports & Adapters)

┌──────────┐
        │ HTTP API │
        └────┬─────┘
             │ Port
    ┌────────▼────────┐
    │                 │
    │   Application   │
    │     Core        │
    │                 │
    └────────┬────────┘
             │ Port
        ┌────▼─────┐
        │ Database │
        └──────────┘

Use when: Need to swap external dependencies, multiple entry points

4. Event-Driven Architecture

Producer → Event Bus → Consumer
              │
              ├─→ Consumer
              │
              └─→ Consumer

Use when: Loose coupling needed, async processing, scalability

5. CQRS (Command Query Responsibility Segregation)

┌─────────────┐      ┌─────────────┐
│  Commands   │      │   Queries   │
│  (Write)    │      │   (Read)    │
└──────┬──────┘      └──────┬──────┘
       │                    │
       ▼                    ▼
  Write Model          Read Model
       │                    │
       └────────┬───────────┘
                ▼
           Event Store

Use when: Different read/write scaling, complex domains, event sourcing

Directory Structure Patterns

Feature-Based (Recommended for medium+)

src/
├── features/
│   ├── users/
│   │   ├── api/
│   │   ├── components/
│   │   ├── hooks/
│   │   ├── services/
│   │   └── types/
│   └── orders/
│       ├── api/
│       ├── components/
│       └── ...
├── shared/
│   ├── components/
│   ├── hooks/
│   └── utils/
└── app/
    └── ...

Layer-Based (Simple apps)

src/
├── controllers/
├── services/
├── models/
├── repositories/
└── utils/

Decision Framework

When making architectural decisions, evaluate against these criteria:

Simplicity - Start simple, evolve when needed
Team Skills - Match architecture to team capabilities
Requirements - Let business needs drive decisions
Scalability - Consider growth trajectory
Maintainability - Optimize for change

Trade-off Analysis Template

Use this template to document architectural decisions:

## Decision: [What we're deciding]

### Context

[Why this decision is needed now]

### Options Considered

1. Option A: [Description]
2. Option B: [Description]

### Trade-offs

| Criteria         | Option A | Option B |
| ---------------- | -------- | -------- |
| Complexity       | Low      | High     |
| Scalability      | Medium   | High     |
| Team familiarity | High     | Low      |

### Decision

We chose [Option] because [reasoning].

### Consequences

- [What this enables]
- [What this constrains]

Validation Checklist

After selecting an architecture, validate against:

Architecture Validation:
- [ ] Matches project size and complexity
- [ ] Aligns with team skills and experience
- [ ] Supports current requirements
- [ ] Allows for anticipated growth
- [ ] Dependencies flow inward (core has no external deps)
- [ ] Clear boundaries between modules/layers
- [ ] Testing strategy is feasible
- [ ] Trade-offs are documented

If validation fails, reconsider the pattern selection or adjust the implementation approach.

Repository: CloudAI-X/claude-workflow-v2
Path: skills/designing-architecture/SKILL.md
Commit: 4c242af

Last updated: 3 days ago
First committed: 7 months ago

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.