Thanks! There's actually a "Soak up rain" and "Stop erosion" goal for the spot-centered default flow to find natives, but it seems like your need is a bit more heatwave resiliency focused?

The alternatives (get it? https://indigene.app/alternatives) section focuses a bit more on the swapping non-natives or turf grasses that do poorly or require intense irrigation during heatwaves, but I really like the idea of adaptation planting.

Generally most natives are inherently better suited for heat waves and warming/drying summers since they tend to need little to no watering once established, but I agree it'd be nice to get a subset of plants that can create shade and help create a bit of an oasis.