Add rate limiting for import

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

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

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

No files, tests, or entry points are identified in the issue. First clarify whether the goal is import rate limiting, more descriptive errors, or both, then locate the import path and its existing error-handling tests; done should be defined by explicit limits and verified error messages.

Written by the indexing model from the issue text.