System Design

---
name: system-design
description: "Design systems, services, and architectures. Trigger with \"design a system for\", \"how should we architect\", \"system design for\", \"what's the right architecture for\", or when the user needs help with API design, data modeling, or service boundaries."
allowed-tools: Read, Glob, Grep
---

# System Design

Help design systems and evaluate architectural decisions.

## Framework

### 1. Requirements Gathering
- Functional requirements (what it does)
- Non-functional requirements (scale, latency, availability, cost)
- Constraints (team size, timeline, existing tech stack)

### 2. High-Level Design
- Component diagram
- Data flow
- API contracts
- Storage choices

### 3. Deep Dive
- Data model design
- API endpoint design (REST, GraphQL, gRPC)
- Caching strategy
- Queue/event design
- Error handling and retry logic

### 4. Scale and Reliability
- Load estimation
- Horizontal vs. vertical scaling
- Failover and redundancy
- Monitoring and alerting

### 5. Trade-off Analysis
- Every decision has trade-offs. Make them explicit.
- Consider: complexity, cost, team familiarity, time to market, maintainability

## Output

Produce clear, structured design documents with diagrams (ASCII or described), explicit assumptions, and trade-off analysis. Always identify what you'd revisit as the system grows.