Buy a Polymarket combo (parlay) via the RFQ gateway

Runs the whole requester flow server-side in one call: creates the RFQ from your chosen leg position ids, accepts the best quote with a signed order, and returns the on-chain result. It is one call rather than two precisely to beat the quote expiry — there is no separate accept step. Set maxPriceCents. Without it you accept whatever blended price the maker returns. With it, a quote worse than your ceiling is refused and nothing trades (a 400). One-time collateral approval. Combos settle against Polymarket's v3 exchange, which ordinary trading never approves. The first execute transparently sets that approval — directly for an EOA, or through the Polymarket relayer for a Kairos deposit wallet. Imported smart-account wallets (Safe / imported Poly1271) cannot execute combos yet and get a 400 explaining so; quoting still works for them. Fees. The Kairos platform fee is resolved from your tier BEFORE the irreversible RFQ is submitted (a tier-lookup outage stops the trade rather than making it free), then accrued against the pUSD spent through the same ledger and sweep as ordinary fills. Auth & scope. Requires trade:execute for polymarket plus the service-token/CSRF/API-key mutation gate, which the API-key triple satisfies automatically.