Optimize types for large datasets

**Problem**
When working with handlers, 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, test, or entry point is named. Start by locating the handler implementations and their current error-message construction, then compare how failures are surfaced. Done means handler errors provide more descriptive messages and the affected behavior is verified.

Written by the indexing model from the issue text.