The default selected tool for turning will have:
Lathe – turn tool tool type.
The proper orientation for the type of cut. See Turn face feature tool orientations for more information.
An 80 degree diamond is preferred but the default selected tool must have an included tip angle of at least a 55 degrees. You can override the tooling selection with a tool with a narrower diamond insert, but such a tool will not automatically selected.
Currently tip radius, tool length and insert grade are not taken into account.
See also How to explicitly set a tool for a turning operation and Tools page for turning.