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.
Install with the open skills CLI (global, non-interactive — available in every Claude Code session):
npx skills add anthropics/knowledge-work-plugins --skill "system-design" -g -a claude-code -yOr manually — copy the SKILL.md below into:
~/.claude/skills/system-design-anthropics/SKILL.md---
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.
---
# 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.
You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.
Use when you have a written implementation plan to execute in a separate session with review checkpoints
Use when executing implementation plans with independent tasks in the current session