Improve error messages in components

**Problem**
When working with models, 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 does not name files, components, error cases, or tests. Start by locating the model-related components and their current error paths, then clarify which messages and cases are in scope before editing. Done means the agreed model errors are more descriptive and the relevant checks pass.

Written by the indexing model from the issue text.