Callback Handler response object

New Callback Handler parametersStarting with SGX API Co-signer image version 3.5.0, as well as all versions of AWS Nitro and GCP Confidential Space Co-signer, the following enhancements have been introduced:

The Callback Handler’s payload includes the signerId, which represents the API user ID (API key) of the API user handling the request. This is particularly useful in high availability configurations with multiple API Co-signers, as it allows the Callback Handler to identify the specific Co-signer that initiated the request.

Below is the response expected from the Callback Handler for any request. If it does not respond within 30 seconds, Fireblocks fails the request.

Parameter	Type	Description
action	string	`APPROVE`: Approves the request. For some configuration requests an approval quorum may be required. `REJECT`: Denies the request. Even if a quorum of approvals is expected, one rejection denies the request. On a transaction signing request, `REJECT` fails the transaction permanently: it is not deferred to a Console user (human signer), and no other signer is asked. Do not use `REJECT` to route a transaction to a manual signer. `RETRY`: Retry the request until it times out, reaches the maximum number of retries, or the Callback Handler returns `APPROVE` or `REJECT`. The default timeout setting is 20 retries every 3 minutes, for a total of 60 minutes. If necessary, Fireblocks Support can adjust the retry interval to a minimum of 30 seconds or a maximum of 1 hour, and the total retry duration up to a maximum of 48 hours. Additionally, retries are performed using identical parameters, so to prevent duplication, make sure your Callback Handler is properly configured to deal with the asynchronous nature of the calls. `IGNORE`: This action is only supported for transaction and configuration approvals, not transaction signing. Dismisses the request without denying it, allowing the following approval requests to be processed. If a quorum is required to approve a request, the other approvers may approve this request independently.
requestId	string	The unique identifier of the call, as received in the approval request.
rejectionReason	string	(Optional) Free text of the reason for rejection. This is used for logging purposes and recorded in the workspace’s audit logs.

Routing a transaction to a Console user instead of the Co-signerThe Callback Handler cannot hand a transaction signing request over to a Console user. If the Policy rule designates an API user as the signer, or a signer group that includes an API user, the Co-signer signs the transaction without routing it to a Console user.Recommended approach: to have a Console user sign, configure the Policy rule so that the designated signer or signer group does not include the API user. This is a Policy configuration, not a Callback Handler response.Approvals are different from signing. IGNORE is valid for transaction and configuration approval requests only, never for signing requests. Returning IGNORE on an approval request dismisses it without denying it, so a Console user (human approver) can approve it independently. Once approved, the Co-signer still performs the signing if it is the designated signer.

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