System Design

What it does

This skill assists in designing scalable, resilient, and efficient systems by guiding architectural decisions and producing structured design artifacts. It breaks down the system design process into distinct steps, including requirements clarification, component identification, alternative evaluation, and document creation. The skill helps users evaluate trade-offs between different approaches and ultimately produce a comprehensive design document outlining key components, decisions, and potential risks.

When to use it

• Designing a new system or major feature from scratch
• Evaluating trade-offs between architectural approaches
• Creating Architecture Decision Records (ADRs)
• Reviewing existing architecture for scalability, reliability, or maintainability concerns
• Decomposing a monolith or planning a migration

Key capabilities

• Requirements clarification: Gathers and clarifies functional, non-functional, scope, and constraint requirements.
• Component identification: Breaks down systems into data stores, services/modules, interfaces, and external dependencies.
• Alternative evaluation: Documents and compares at least two options for each significant architectural decision based on criteria like complexity, scalability, operational cost, and team familiarity.
• Design artifact generation: Produces a structured design document including context, requirements, architecture diagrams, key decisions, data models, API surfaces, risks & mitigations, and open questions.
• Review checklist: Provides a list of items to verify before finalizing the design (e.g., single responsibility, failure modes, security boundaries).

Example prompts

• "I need to design a new user authentication system. Can you help me outline the requirements?"
• "We're considering using microservices for our order processing pipeline. What are some architectural trade-offs I should consider?"
• "Can you generate an Architecture Decision Record for choosing between relational and NoSQL databases for storing product catalog data?"

Tips & gotchas

• The skill emphasizes clarifying requirements upfront; be prepared to answer questions about the system's purpose, constraints, and scope.
• The output is a structured design document – expect a detailed outline rather than a fully implemented solution.
• The skill recommends documenting at least two options for each significant architectural decision to ensure trade-offs are explicitly considered.