Use SmartEnum as discriminator in various places

In EF Core we can use HasDiscriminator and map entity types to specific value

In System.Text.Json we need something like JsonSubTypes to hand deserialization

Not sure if this makes sense....

The issue mentions EF Core discriminator mapping and System.Text.Json polymorphic deserialization, but names no files or tests. First clarify which integration is intended and define concrete supported scenarios; done should include an agreed scope and tests or examples covering the selected discriminator behavior.

Written by the indexing model from the issue text.