lld

Amazon Low Level Design (LLD) Skill

Use this skill when creating detailed technical specifications for software components. LLD documents bridge the gap between high-level architecture and actual code implementation, providing engineers with everything they need to build.

Template: See docs/templates/lld-template.md for the authoritative template structure.

When to Use This Skill

• After HLD is approved and detailed implementation specs are needed
• When engineers need complete API specs, database schemas, and sequence diagrams
• When defining component interfaces and data flows
• When creating specifications detailed enough for immediate implementation

Document Structure Summary

Create a ~6-page document (3000-3500 words) with these sections:

1. Title & Metadata - Component/service name, author, date, version, related HLD
2. Introduction (½ page) - Context, scope, audience, terminology
3. Detailed Component Design (2-3 pages) - Responsibilities, dependencies, interfaces, data flow, error handling, configuration
4. Data Models & Schemas (1-1.5 pages) - Entity definitions, database schemas, indexing strategy, serialization
5. API Specifications (1 page) - Complete endpoints with request/response examples, error codes, validation
6. Sequence & State Diagrams (½ page) - Key flows, state machines
7. Operational Considerations (½ page) - Monitoring metrics, logging, performance targets, deployment
8. Open Issues/Assumptions (½ page) - Issues, assumptions, prototyping needs

Writing Style

Quality Checklist

• All components have clear responsibilities and boundaries
• Data flows are explicitly documented with state transitions
• APIs include complete request/response specifications
• Database schemas include proper indexing strategies
• Mermaid diagrams accurately represent system flows
• Error handling covers all failure scenarios
• Performance and monitoring requirements are specified
• Word count: 3000-3500 words

Output Location

docs/design/[component-name]-lld.md