The vSphere Tagging API (CIS) is all that you need for all CRUD and GET operations.
If you wish to retrieve the Name/Description, you just perform a GET on the TAG ID
e.g.
https://vcsa.primp-industries.local/api/cis/tagging/tag/urn:vmomi:InventoryServiceTag:6a5eb4ea-d592-4365-9c3f-880ba3a4ef44:GLOBAL
Another useful tool to play w/vSphere REST API without having to write any code is Developer Center (built into vCenter Server via vSphere UI)