Update data documentation

**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.

The issue names route handling and error messages but does not identify files, tests, or entry points. Start by locating the route-related code and its current error handling; done means the resulting errors provide more descriptive debugging information, with coverage for the changed behavior.

Written by the indexing model from the issue text.