Improve error messages in core

**Description**
Currently models lacks proper monitoring support.

**Proposed solution**
Add configurable monitoring with sensible defaults.

**Priority**: Low/Medium

The issue does not name files, tests, or an entry point for the proposed monitoring support. First map the core model code and existing configuration and monitoring behavior, then clarify the monitored events, configuration surface, defaults, and acceptance checks before implementation.

Written by the indexing model from the issue text.