Not much.

If you are an owner entering into a construction contract, the contract will normally require the contractor and the sub-contractors to produce certificates of insurance naming you, the owner, as an additional insured party. However, a certificate of insurance is issued by an agent and doesn’t bind the insurance company, at worst. And doesn’t adequately disclose the coverage and exclusions in the policy, at best. You would be better off getting a copy of the full policy, except that the insurance company won’t have compiled it yet. But you can ask for a sample policy form and forms of the various endorsements (i.e., amendments) because those should be available more quickly.