Add a check before the purchase runs.

01 / Access

Request the private SDK.

Authorized users receive a packed SDK and setup help for Node 22.16 or newer. Public npm installation and a production purchase/model API are not available yet. The hosted playground uses synthetic fixtures.

02 / Host setup

Provide the server-owned checks.

authenticate

Resolve the current authenticated caller on every invocation, including receipt replay. Approval eligibility is checked separately.

read

Independently read the original approval and current checkout evidence. Client-supplied text is not spending authority.

semanticGate

Configure the semantic check and any model access your host uses.

claim

Synchronously and atomically claim the approval and budget. A Promise is not accepted for this callback; durable state and cross-process coordination belong to your host.

Persist authority, idempotency and reconciliation in your own backend. The wrapper does not supply a managed identity service, payment executor or cross-process database.

03 / Purchase boundary

Wrap the function you already use.

After authorized SDK setup, the call shape is:

const buy = guardPurchase(existingBuy, {
  authenticate, read, semanticGate, claim
});

const result = await buy({ operationId, approvalId });

This shows the wrapper interface, not a complete setup. Implement and configure the host callbacks first. The wrapper performs the checks and invokes existingBuy when approved. Do not execute the purchase again from its result.

04 / Outcomes

Separate the decision from execution.

Decision results are approved, blocked or needs_review. Execution outcomes are not_started, succeeded or unknown.

If execution is unknown, reconcile the operation with your purchase system before another payment attempt. Do not automatically retry. Your backend enforces the result and owns recovery.