Improve error messages in handlers

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

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

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

Start by locating the handlers and the type-related error paths referenced by the issue. Review the existing error handling and determine which cases need more descriptive messages; done means the relevant failures provide useful debugging context and the project’s checks pass.

Written by the indexing model from the issue text.