| name | architect |
| description | System architecture design skill with pattern recognition, trade-off analysis, and documentation. Use when designing new features, evaluating architecture decisions, or planning system refactoring.
|
| license | MIT |
Architect Skill — System Design Expert
This skill provides comprehensive architecture design guidance with evidence-based decision making.
Design Principles
SOLID
- Single Responsibility: One reason to change
- Open/Closed: Open for extension, closed for modification
- Liskov Substitution: Subtypes must be substitutable
- Interface Segregation: Many specific interfaces > one general
- Dependency Inversion: Depend on abstractions, not concretions
CUPID
- Composable: Works well with other components
- Understandable: Clear purpose and usage
- Predictable: Behaves as expected
- Idempotent: Same operation, same result
- Domain-focused: Names and structure reflect the domain
Architecture Patterns
Monolith vs Microservices Decision Matrix
| Factor | Monolith | Microservices |
|---|
| Team size | Small (1-5) | Large (5+) |
| Deployment frequency | Low | High |
| Scaling needs | Uniform | Variable per component |
| Complexity | Low | High |
| Data consistency | Easy | Hard (eventual) |
Recommended Patterns by Domain
| Domain | Pattern | Why |
|---|
| API Layer | Hexagonal/Clean | Testability, flexibility |
| Data Access | Repository Pattern | Abstraction from storage |
| Events | Event Sourcing | Audit trail, replay |
| Caching | Write-through | Consistency |
| Auth | RBAC + ABAC | Fine-grained control |
Decision Record Template
## ADR-[N]: [Decision Title]
### Status: PROPOSED | ACCEPTED | DEPRECATED | SUPERSEDED
### Context
[What is the issue that we're seeing that is motivating this decision?]
### Decision
[What is the change that we're proposing/making?]
### Alternatives Considered
1. [Alternative 1]: [Pros] / [Cons]
2. [Alternative 2]: [Pros] / [Cons]
### Consequences
**Positive**: [Benefits]
**Negative**: [Costs/Risks]
**Neutral**: [Side effects]
### Reversibility
[How hard would it be to undo? What is the blast radius?]
Design Review Checklist
When NOT to Use
Do NOT use this skill when:
- Writing application business logic (use domain-driven skill for complete business modules with all sub-modules)
- Designing database schemas (use database-design skill for normalization, indexing, and query optimization)
- Reviewing code for quality issues (use code-review skill for comprehensive code audits)
- Writing API endpoint implementations (use api-design skill for REST/GraphQL endpoint patterns)
- Performing security audits (use security-auditor skill for vulnerability analysis and threat modeling)
- Analyzing deployment configurations (use deployment skill for CI/CD pipelines and infrastructure)
- Writing SQL queries (use sql-best-practices skill for query optimization and N+1 prevention)
- Reviewing git workflows (use git-workflow skill for branching strategies and commit conventions)
- Redesigning existing websites (use website-redesign skill for UI/UX improvements from URLs/screenshots)
