Consider deprecating old store API

**Problem**
When working with middleware, 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 old store API and the middleware error-handling path in the repository. Clarify whether the intended work is deprecating the API, improving error messages, or both, then identify the relevant tests or add coverage for the agreed behavior. Done means the scope is decided and the resulting errors provide the required debugging detail.

Written by the indexing model from the issue text.