120 architecture decision walkthroughs for senior, staff & principal interviews — the open-ended "how would you decide" questions where there is no single right answer and you are scored on judgment, not recall. Each follows a decision path: Context → Clarify first → Trade-offs → Recommendation → Reversibility → De-risk, closing with the meta-signal the interviewer is really scoring. The staff+ move is to interrogate the question before solving it — and to be willing to give the unfashionable "don't build it" answer.