When does Rehab/improvement trigger assessment?

[Arjun K.]

I am closing on a property in Austin. This property is being acquired for ~$200K and will require either $25K or $50K work (depending on which path I go down). $30K is new painting, flooring, landscaping, kitchen, baths, putting in HVAC. $50K is opening up some of the floorplan (knocking down walls -- not putting in new ones), moving furnace/HVAC to attic, higher-end finishes. Garage is already converted.

How can I tell whether any of the repairs will automatically trigger a higher assessment, and what the methodology will be?

Thanks in advance!