How to Frame a System Design Problem Before Choosing Components
Turn an ambiguous booking request into explicit outcomes, constraints, and a first decision. Includes a printable Design Decision Worksheet.
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Find a useful question. Work toward a clearer decision.
Practical lessons for interview preparation and architecture at work. Read every article freely. Create a free account to download the PDF worksheets.
Compare Architecture Alternatives Under the Same Constraints
Use hard constraints, a small evidence table, and a reconsideration trigger to make a design choice that another engineer can examine.
The Request Timed Out. Did the Action Happen?
Design recovery for a refund or booking whose outcome is unknown. Separate a retry from a new business action and reconcile before guessing.
Your Retrieved Sources Disagree. What Should the System Do?
Separate relevance from applicability when retrieved policies conflict. Make authority, scope, effective dates, and uncertainty visible.
Define the Boundary Between an Agent Draft and a Real Action
Specify what an agent may prepare, what authorizes execution, and what happens when approval or verification is unavailable. Includes a printable review worksheet.
Measure Cost per Successful Task Before Optimizing Tokens
Compare two hypothetical AI workflows using the same quality bar, full run cost, and verified task outcomes. Includes a worked calculation.
A look inside the free PDF
Design Decision Worksheet
Put a real design decision on the page. Start with the outcome, trace one interaction, and name what must remain true.
The complete worksheet adds constraints, alternatives, the recommendation, failure tests, and the evidence that would reopen your decision.
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Outcome and scope
Who needs what outcome? What is included in this decision, and what is outside it?
Critical interaction
Trace one request from the user to the recorded result. Mark who owns the decision.
What must remain true?
State the invariant or required behavior. Example: two overlapping bookings for one room cannot both be confirmed.
Read the prompts here. Use the PDF to record your own reasoning.