How can I customize Gateway Responses using Chalice?

When I raise exceptions, like BadRequestError, Chalice uses the model from Gateway Responses to show the error, usually `{"message":$context.error.messageString}`. I'd like to change the string from Chalice instead of go to admin request by request and modify everything. There's some way?

Start with Chalice's handling of BadRequestError and the AWS API Gateway Gateway Responses model described in the issue. Determine whether Chalice exposes a supported way to change the error message template; if not, document the configuration boundary or limitation.

Written by the indexing model from the issue text.