Refactor config for better readability

**Problem**
When working with parsers, 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 no files, tests, or parser entry points. Start by locating the parser configuration and existing error-handling paths, then determine which errors need more descriptive messages. Done means the refactor improves parser error messages and the relevant behavior is covered by tests.

Written by the indexing model from the issue text.