Improve middleware performance

**Problem**
When working with auth, 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 middleware authentication error-handling entry points in the repository. Review how current errors are produced and define the missing descriptive details; done means the relevant errors provide more useful debugging messages and the behavior is covered by appropriate validation.

Written by the indexing model from the issue text.