In Texas, the mineral estate is dominant over the surface. The purpose of this agreement is to reverse this so that the surface use becomes dominant over the minerals. If you do not own any surface and are not being compensated financially, then why would you want to possibly impair mineral development? Good faith does not have any legal meaning except as interpreted by the court. Signing an agreement that binds you to work together in good faith about the surface use vs mineral development means that you can be sued by the solar company for failing to agree with them. You could sue them, but you would have to prove financial loss. If your minerals are under lease to Diamondback or another company, then agreeing to limit surface use could open you up to damage claims from your lessee. Tell the solar company to come to you with a comprehensive explicit proposal about the solar vs mineral use of the surface and compensation and then you can consider it after consulting with an attorney. Your lessee can review the plan and discuss how much and where surface is required for wellpad(s), pipelines, electric lines. A lot of this depends on the gross acreage and your net mineral acreage in the tract. This can be quite complex. As a general matter, it is not a good idea to sign any legal agreement that you do not fully understand.