--- name: designing-architecture-479f4abc528c description: 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. --- # 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: 1. **Simplicity** - Start simple, evolve when needed 2. **Team Skills** - Match architecture to team capabilities 3. **Requirements** - Let business needs drive decisions 4. **Scalability** - Consider growth trajectory 5. **Maintainability** - Optimize for change ## Trade-off Analysis Template Use this template to document architectural decisions: ```markdown ## 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. --- Source attribution: CloudAI-X Original project: https://github.com/CloudAI-X/claude-workflow-v2 License: MIT License information: https://opensource.org/license/mit Original upstream instructions; downloaded from Mega AI Hub. ## Upstream license notice MIT License Copyright (c) 2026 Gabriel Moreira Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # Mega AI Hub resource metadata Creator / publisher: CloudAI-X Original project: https://github.com/CloudAI-X/claude-workflow-v2 Attribution basis: Upstream repository explicitly recorded in package mirror path Fields of work: Development & Engineering, Product Management, Project & Program Management Roles: Backend Developer, Full-Stack Developer, Product Manager, Project Manager, Technical Product Manager Specialties: Backend Tools: Tool not specified Country applicability: Country not specified Classification basis: Source catalog labels Instruction SHA-256: f34d405afa18ada0ef97bbf4e37242877ecd2cad29caadc23b33fe41bbd07d31