// Illustrative TypeScript: the model proposes; code authorizes.
async function handleRefund(input: Request, actor: User) {
  const route = await detectRisk(input);
  if (route === "unsupported") return safeFallback();

  const raw = await model.generate({
    instructions: REFUND_POLICY,
    input,
    tools: [{ name: "propose_refund" }], // no payment credential
    outputSchema: RefundProposal,
  });

  const proposal = parseWithSchema(raw, RefundProposal);
  const order = await orders.readForUser(proposal.orderId, actor.id);

  // Deterministic policy: never delegated to the model.
  assertRefundable(order);
  assertCurrency(proposal.amount, order.currency);
  assertWithinLimit(proposal.amount, 50);
  assertDailyBudget(actor.id);

  const approval = await approvals.request({
    actor,
    proposal,
    evidence: { deliveryState: order.deliveryState },
  });
  if (!approval.granted) return explainNoAction();

  const result = await payments.refund({
    orderId: order.id,
    amount: proposal.amount,
    idempotencyKey: approval.id,
  });

  await audit.record({ actor, proposal, approval, result });
  return sanitizeReceipt(result);
}