Other Insurance: "Additional Insured" Under a Building Contractor's Liability Policy

My question involves insurance law for the state of: New York.

Greetings. I am a homeowner hiring a contractor to replace my roof. I asked the contractor to designate me as an additional insured under his liability policy.

He sent me a Certificate of Liability Insurance (ACORD 25 (2016/03)). My name and address appear under "Certificate Holder." The description is filled in with this: "Certificate holder included as additional insured. Subject to policy terms and conditions." In the line for Commercial General Liability, the box for Additional Insured is checked.

I understand that this certificate is not a contract, and it, by itself, does not alter the insurance coverage or confer any rights on me. So I asked the contractor for the policy endorsement that deals with additional insureds.

He sent an endorsement whose language seems acceptable. My only question is whether the endorsement applies to me. The schedule that identifies the additional insured and the location is filled in with this blanket language:

Name of Additional Insured:
As required by a legally enforceable written agreement entered into prior to commencement of the Named Insured's work
Designated Project/Location to which this endorsement applies:
All Projects and Locations

My contract with the contractor does not say anything about naming me as additional insured. But the Certificate of Liability Insurance does. Do I qualify as an additional insured under this endorsement?

With many thanks for your thoughts.

Other Insurance: "Additional Insured" Under a Building Contractor's Liability Policy