System capabilities
The dot object, aliases, and permissions.
Orientation
System calls use .Name(args) or an @_ form. The system context can expose aliases while a sandbox withholds capabilities that a script should not receive.
A dot-prefixed capability is supplied through the current system context; inspect one call before depending on a larger plugin surface.
A worked example
The final line is the displayed value; the earlier lines set up the experiment. Keep the setup visible so you can tell whether a name, a cell, or a collection is being reused when the expression changes.
Read the result
Use the reference to distinguish system functions from user-defined uppercase callables.
Compare a direct arithmetic expression with its dot-capability form.
Keep going
Continue with Diagnostics and tests or Assertions and symbolic specs.