Actions and triggers can refer to hardcoded knowledge base names (for example, cat('Admin KB', 1) ) and to variable knowledge base names (for example, cat($KBNAME, 1)). Defining the values of knowledge base variables as external knowledge bases ensures that they are available for selection in rule window option lists.
If your decision plan rules refer to knowledge bases as content fields or temporary variables, add the possible values of these variables (that is, the knowledge base names) to a list of external knowledge bases.
To define external knowledge bases: