Agent ignores codebase conventions
You've joined a team owning a 400k-line Ruby on Rails monolith and you need an AI agent to add a new billing-proration feature. The agent's first attempt invents a PricingService that doesn't exist, duplicates logic already in app/services/billing, and ignores the team's convention of routing all money math through a Money value object. Describe how you'd give the agent the right CONTEXT so it succeeds, and what specifically went wrong on attempt one.
prorate_upgrade_cents(old_plan_cents: int, new_plan_cents: int, days_elapsed: int, days_in_cycle: int) → int[1000,3000,0,30]out2000[1000,3000,15,30]out1000[3000,1000,15,30]out-1000Treat the AI’s output as a draft to verify, not an answer to trust. Name the specific flaw and the input that triggers it, say how you’d catch it (tests, edge cases, reading critically), and how you’d re-prompt or decompose to get it right.
Vibe & agentic: describe the solution in plain language (or narrate it) and the coach grades your approach.