Before starting, you need to know what geographic or projected coordinate system needed to use for the tool. Let's assume that WGS-1984 will be used which has a WKID of 4326. It's a very common geographic coordinate system, so I won't go into any details about WGS-1984.
Usings the geographic coordinate systems references from the above provided links, create a spatial reference object based on the WKID.
Example: Using Factory Codes
from arcpy import env
WKID = 4326 # WGS-1984
sr = arcpy.SpatialReference()
sr.factoryCode = WKID
env.outputCoordinateSystem = sr
Now the default output coordinate system in WGS-1984.
There are many other ways to create a spatial reference obeject and they can be found here.