Improve error messages in utils

**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 only points to lib and does not name a utility file, error path, or test. Start by locating utility code and its existing error handling; done should mean the relevant errors provide more descriptive messages and the existing checks still pass.

Written by the indexing model from the issue text.