There are three documents at the Yale Law School, Avalon project, that seem to contain the mutual obligations of the USA and Cuba as regards Guantanamo Bay. These are
The texts of the Lease
1. The February 23, 1903 Lease part 1, the parcels
2. The July 2, 1903 Lease part 2, obligations
Treaty of International Relations between the two countries
3. The May 29, 1934 Treaty of Relations which modified and replaced the Treaty of Relations signed at Habana, May 22,1903.
Both mention the lease.