Authorize agent spend before the provider call.

1import { generateText } from "ai"
2import { Unprice } from "@unprice/api"
3
4const unprice = new Unprice({ token: process.env.UNPRICE_TOKEN })
5
6// 1. Reserve the most this model call may cost.
7const { result: reservation, error } = await unprice.reservations.reserve({
8  customerId,
9  maximumAmountMinor: 10, // $0.10 ceiling, held against the customer's budget
10  idempotencyKey: messageId,
11})
12
13// Hard deny. Return here and the provider is never called.
14if (error) {
15  return new Response("Customer budget unavailable", { status: 402 })
16}
17if (!reservation.allowed) {
18  return new Response("Customer budget unavailable", { status: 402 })
19}
20
21// 2. Spend only after the reservation succeeds.
22const generation = await generateText({
23  model,
24  prompt,
25  maxOutputTokens: 2_000,
26})
27
28// 3. Capture actual usage and release the unused amount.
29const settlement = await reservation.settle({
30  featureSlug: "ai-output-tokens",
31  eventSlug: "completions",
32  id: messageId,
33  properties: {
34    inputTokens: generation.usage.inputTokens,
35    outputTokens: generation.usage.outputTokens,
36  },
37})
38
39if (settlement.error) throw settlement.error
40
41return Response.json({ text: generation.text })