Many scripts have special pieces of information that are either passed into the script from HL or that the script must specify for subsequent use by HL. For example, a script-based label portal has two such values. On entry, the script is informed whether it is being applied to either a thing or a pick, since that distinction is important for some scripts. On exit, the script must tell HL what the final text is that should be displayed within the label.
Whenever a value needs to be passed into or out of a script, a "special symbol" is used. Special symbols behave exactly like variables, so they can be used just like a variable within the script. The name of each special symbol is always prefixed with the '@' character, which is followed by the name of the special symbol. For example, to access the special symbol "value", the syntax would be "@value".
The set of special symbols varies for each script, as will their use, with some scripts having zero special symbols and a few having many. The exact symbols for a given script are specified with the details for each script within in Kit Reference documentation.