Improve parsers performance

**Problem**
When working with validation, 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 does not name any files, parser entry points, or tests. Start by locating parser validation and existing error-handling code, then clarify whether the goal is parser performance, more descriptive validation errors, or both. Done should be defined by maintainers with focused tests covering the revised behavior.

Written by the indexing model from the issue text.