Improve helpers performance

**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.

Start in lib and trace the helpers referenced by the issue. Establish which operation is slow and which failure cases need clearer messages before defining the change. Done means a measured performance improvement and more descriptive error handling, with relevant existing checks updated if they are present.

Written by the indexing model from the issue text.