Consider deprecating old core API

**Problem**
When working with store, 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 store and core API error-handling entry points in the repository, since no files or tests are named. Review how current errors are produced and identify the expected detailed messages; done should mean the relevant failures provide more descriptive debugging context and are covered by tests.

Written by the indexing model from the issue text.