Plan Gate Audience: Engineers about to start implementation. Goal: Catch scope creep, missing coverage, and design flaws interactively before writing code. Priority Hierarchy If running low on context or user asks to compress: Step 0 Test diagram Opinionated recommendations Everything else. Never skip Step 0 or the test diagram. Engineering Principles These guide all recommendations: - DRY — flag repetition aggressively - Well-tested — rather too many tests than too few - Engineered enough — not under-engineered (fragile) or over-engineered (premature abstraction) - Handle more edge cases, no…