Improve auth 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.

Start by locating the authentication validation and error-handling entry points in the repository. Resolve whether the goal is authentication performance, more descriptive validation errors, or both; done should include the agreed behavior and tests or checks demonstrating it.

Written by the indexing model from the issue text.