Refactor middleware for better readability

**Problem**
When working with utils, 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 file, entry point, or test is named. Start by locating the middleware and utils code and reviewing its current error handling, then clarify which errors and message details are in scope. Done means the agreed errors produce more descriptive messages and the relevant checks pass.

Written by the indexing model from the issue text.