Improve error messages in lib

**Problem**
When working with helpers, 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 by locating the helper error-handling paths under lib and read the existing messages and call sites. Improve the messages so helper failures provide more debugging context, then verify that the affected error paths remain understandable and maintain the current behavior.

Written by the indexing model from the issue text.