Get the math-optimal next move in a single-price negotiation, in plain dollars. Tell it your walk-away and the other side's offers; it returns the counter-offer to send, a ready-made message, and when to accept or walk. Validated ~12% better head-to-head (n=20 paired LLM negotiations, 95% CI +6.5-17.4%, p<0.0001). Any counterparty.