- When an entity’s state is
unknownit means the entity has not acquired/computed a value. - When an entity’s state is
unavailableit usually means the associated device is offline and not reporting values.
What is the undefined state you mentioned (because it’s not common to all entities)?
If you want a filter that ensures an entity’s state value is not unavailable or unknown, it should be called something more comprehensive than is_available because that implies it’s only checking for not unavailable.
Perhaps is_nominal which implies the value is nominal (“normal”) as opposed to non-nominal (“abnormal”).