Check

The entitlement plane: one local read, no provider round trip, and the balance the customer has of one feature.

Source: packages/paykit/src/Billing/Check.binding.ts Kind: Binding · Product: Usage · Provides: Paykit.Check

The entitlement plane: one local read, no provider round trip, and the balance the customer has of one feature. Check never records usage — TrackUsage is the write, and it judges the allowance in the transaction that records it. Asking before acting is how a caller shows a price, not how it protects a quota: that protection is TrackUsage refusing, or a lock.

Asking before doing work

const check = yield* Paykit.Check(account);
const answer = yield* check({ featureId: "messages", requiredBalance: 1 });
if (!answer.allowed) return showUpgrade(answer.standing, answer.balance.nextResetAt);

Reserving what the work will cost

{ lock: true, idempotencyKey } places a hold when the answer is allowed, so a second caller cannot spend the units. Finalize it with Paykit.Balances(account).finalize.