How to handle errors in custom Business Logic Lambda (GraphQL API)

Please extend the documentation at https://docs.amplify.aws/cli/graphql/custom-business-logic/ to include details of how (best) to throw (or handle) errors in the Lambda

E.g. if my custom lambda throws an application error, should I trap it and return some sort of response?

Current behaviour is that a Lambda:Unhandled error is returned with the message of the thrown error.

Is there a better solution?