Use this when the user wants to check a proposed payment against explicit rules before sending it, for example whether the amount, recipient, asset or network matches their policy or would exceed their limit. Compares the proposal with the user's structured policy and returns ALLOW, REQUIRE_APPROVAL or BLOCK. It does not send, sign or authorize payments, perform sanctions screening, or certify safety or compliance; ALLOW is a policy comparison only. No external lookups, storage or receipt. Use public addresses and decimal amounts, not atomic units. Resource URLs are never fetched and must not contain credentials or private query parameters.