Improve error messages in models

**Description**
Currently lib lacks proper serialization support.

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

**Priority**: Low/Medium

Start by reading the code under lib and locating the model-related entry point. Clarify which model data needs serialization and how configuration should be supplied before changing behavior. Done means serialization is configurable and has sensible defaults, with the relevant model flows still working.

Written by the indexing model from the issue text.