He is not authorized to make improvements without your permission, which should be given in advance, in writing, and detailed enough to ensure there's no confusion about what's authorized, who's paying for it, how it will be done, when it will be done, and what happens with the improvement after termination.

I cannot legally trees unless provided explicit permission by property (tree) owner.Gets tricky with property boundary trees.

The other trend I"ve seen a few times recently is short term rentals where our clients are leasing a property and being the main tenant and then sub-leasing (with landlord permission) as an air bnb.

If you want to pre-market, you will need permission from the seller (builder).

You can enter a unit for required maintenance without permission.

However, the contractor should not have built that wall without your permission.

Get his verbal permission to do the SNAP application. 

We cannot advertise the pending property when representing the buyers unless we have permission from the listing agent.  

If you have written permission from seller to represent you in the discussion as sellers authorized person to discuss on sellers behalf, it might be okay, you may save some money.

The city of San Diego, versus other cities in San Diego county, has become quite ADU permissive.