Add configuration options for import

**Problem**
When working with lib, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

The issue does not identify files, tests, an import entry point, or the configuration format. Start by locating the import implementation and its existing error-handling tests, then confirm which configuration options and error cases are in scope. Done means the intended import options are documented and detailed errors are covered by tests.

Written by the indexing model from the issue text.