Handle edge cases in filtering

**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 filtering entry points and tracing how filtering errors are currently handled. Reproduce the relevant edge cases, then confirm that each produces a more descriptive error message and that the existing checks still pass.

Written by the indexing model from the issue text.