Refactor routes for better readability

**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 route definitions and the validation and error-handling entry points, since the issue names no files or tests. Review how current validation failures are reported; done means the affected errors are more descriptive and existing behavior remains intact.

Written by the indexing model from the issue text.