Improve error messages in models

**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.

Start by locating the parser implementations and their current error-handling paths. Review how parser failures are reported, then define what additional context the messages should provide and verify that representative parser errors become more descriptive.

Written by the indexing model from the issue text.