Improve auth performance

**Problem**
When working with routes, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

No files, tests, or entry points are named. Start by locating the route and authentication error-handling paths, then reproduce the current messages and identify the expected descriptive output; done means the relevant errors provide clearer debugging context with coverage for the changed behavior.

Written by the indexing model from the issue text.