Consider deprecating old routes API

**Problem**
When working with components, 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 or test is named. Start by locating the old routes API and the component error-handling entry points, then clarify with maintainers which routes should be deprecated and what detailed error messages are required; done should include agreed deprecation behavior and improved messages.

Written by the indexing model from the issue text.