The debugger panel allows watching the event
processing inside an agent. The window is made up of the agenda area,
the agenda control area in the middle and the details view at bottom (see
Figure 4.4, “The Beliefs Panel of Introspector”.
The agenda contains all current action entries of the agent, whereby entries in light-grey denote already processed actions. In addition it can be seen whether entries currently have a valid precondition and thus can subsequently be executed; otherwise they are marked as (invalid). Such invalid actions will not be executed, but just ignored by the execution mechanism. To see some more information about an agenda action you can click on it and inspect its values in the details view. In addition to observing the agent's internal behaviour the tool also allows you to control the agenda execution by performing actions in step mode. If the execution mode is set to step or cycle you can use the forward button to execute as many steps as shown in the execute <n> agenda actions choice. The difference between step and cycle mode concerns only the execution of ProcessEventActions that are decomposed to finer-grained sub steps (FindApplicableCandidatesAction, SelectCandidatesAction and ScheduleCandidatesAction) when the step mode is activated. Therefore, the step mode allows you to examine the details of the BDI plan selection process what can be helpful in understanding and explaining unexpected application behaviour. The open steps status bar shows the progress of the action execution by highlighting the number of steps the agent still has to perform whereas in the the processing state line it can be seen if a step is currently requested or has been finished.