Improve validation performance

**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.

No files, tests, or entry points are named. Start by locating service validation and the existing error-handling paths, then determine where validation performance and message detail are measured. Done means the relevant validation is faster and its errors are more descriptive, with tests covering the changed behavior.

Written by the indexing model from the issue text.