Improve error messages in types

**Feature request**
It would be great to have notifications for models.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_notifications` with default `false`.

The issue names no files, tests, or entry points, and its title conflicts with the feature request. Start by locating configuration handling and the model notification flow, then determine how existing options are tested. Done means the new enable_notifications option defaults to false and the requested notifications work as described.

Written by the indexing model from the issue text.