Prompt - Validate a Business Idea Fast

Act as a startup mentor. Here's my business idea: [DESCRIBE]. Stress-test it honestly: who exactly is the customer and how painful is their problem, is this a vitamin or a painkiller, who are the alternatives (including 'do nothing'), what's my likely unfair advantage, what would have to be true for this to work, and what's the single cheapest experiment to validate the riskiest assumption this week? Be candid, not encouraging by default.