System Design Card 357 — Requirements Clarification / Assess
Concern
Every design starts with defining what must be true for the system to be considered successful. A notification system for security alerts is a different system from a marketing fanout service even if both 'send messages'.
What Assess means for this concern
In BASIC, the Assess step is where you identify the main architectural pressures and choose which trade-offs are actually important. For Requirements Clarification, that means the candidate should make this concern visible at the right moment instead of bolting it on at the end.
Design move
A good move is to compare plausible approaches before committing. Tie the concern back to the user flow, the workload, and the dominant trade-off. That keeps the design grounded and makes it easier for the interviewer to follow why a cache, queue, replica, partition, or rate limiter is actually necessary.
Common miss
The common miss is skipping functional and non-functional requirements and drawing architecture into a vacuum. BASIC helps because the staged flow keeps this concern proportional to the prompt and connected to the rest of the architecture.
BASIC prompt
“When I reach the Assess stage, how does Requirements Clarification change the architecture, the trade-offs, or the review checklist?”