Optimize config for large datasets

**Problem**
When working with api, 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 no files, tests, or concrete entry point beyond the API. Start by locating the API error-handling paths and determine which errors need more detail; done means the requested messages are specified and the relevant behavior is covered by verification.

Written by the indexing model from the issue text.