Interface IErrorResponder

A request-scoped error responder: writes an error response in the application's configured format.

Implemented by @setu-ts/exceptions from the formatter and content type its errorHandler resolved at factory time. The interface — not a formatter reference — is what common carries, because a package without exceptions cannot construct the HttpError a formatter needs: a plain Error carries no statusCode, so a formatter would answer 500 for a tenant 400 and maskInternalErrors would then mask it.