Consider deprecating old parsers API

**Problem**
When working with utils, 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 names only the utils area and an old parsers API; start by locating those entry points and reviewing the current error handling. Done means the deprecation direction is settled and error messages provide the requested debugging detail, with relevant validation added where the existing code supports it.

Written by the indexing model from the issue text.