The site appears straightforward
A routine-looking yard still needs an explicit preparation scope. Ask what will be removed or retained and how the support will be made suitable for the intended slab. The contractor should connect preparation to the design rather than offer a layer description without explaining the underlying ground. Uniform support is a construction objective, not something a homeowner can certify by looking at a smooth surface.
Notice next: Review the specified preparation and who checks it. Request safe records before concealment and keep the relevant drawings and changes together.