How to get response, when the agreement is signed by the SIGNER

Does adobe sign provide any better way to send a response when the Agreement is signed ?
postSignOption has only the redirecturl. But we want to add some query parameters (like externalId, signedtime) in the url or  receive a response json when the agreement is signed

Right now the only option i can see is keep polling for every 1 hour using the agreeementid/externalid and fetch the status. But this will not be a good design.