Action List Parameters allow you to make an action list behave as a function of specific values when you call it.
The scope of an action list parameter is confined to the actions within the Action List. Action List Parameters can be modified from script in the same manner as FinalBuilder variables.
Action List Parameters can be accessed anywhere that FinalBuilder variables can be used. Action List Parameters take precedence over  FinalBuildervariables of the same name. The syntax to access an action list parameter outside of script is the same as for a variable, ie %ParameterName%.
Action List Parameters are available on any action list except Main and OnFailure.
To view or modify action list parameters you can either:
1. Right-click on the action list tab and select "Action List Parameters...", or
2. Select the "Action List Parameters..." menu item from the Project menu.
In the above example, the variables %SOURCEPATH% and %BUILDNUM% are available to any actions in the action list with these parameters.
To run an action list, use a "Run Action List" action (available in the "Flow Control" action types category). The Run Action List action's property page allows you to specify the value of each action list parameter:
Note:
An alternative way to access Action List Parameters in fields of actions is by using the following syntax: #Parameter#
This syntax is deprecated. To escape this sequence, use an extra #, eg. ##Parameter#.