Reflection can be used to write custom static-analysis routines to verify things about your program.  Here are some examples.

Dead code detection

You can check whether there are any unused tasks in your program.  For example, the predicate:

DeadCode ?task: [CompoundTask ?t] [Not [TaskCalls ? ?t]]

is true if ?task is a task with methods that nothing calls.  Given that, you can add:

[Not [DeadCode ?]]

to your unit tests to alert you if you have dead code in your program.

Custom checkers

This more often gets used to check for relationships between specific types of tasks.  For example, suppose you are implementing a storylet system, that breaks stories or quests up into little fragments (the storylets) with preconditions for when they can be used.