Add unit tests for hooks

**Problem**
When working with services, 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 hooks, services, error handling, and unit tests but provides no file, test, or entry point. Start by locating the existing hook tests and service error-handling paths, then clarify the expected messages; done means the agreed error cases have more descriptive messages with unit-test coverage.

Written by the indexing model from the issue text.