A guard condition is an evaluation, usually based on business logic, that the flow processor makes before performing an action. The return value of the guard condition (a boolean) determines whether the flow processor follows its normal flow or performs an alternative flow. The guard condition uses  flow modifiers (see Flow modifiers) to determine what to do such as performing a different action or changing the state to another specified state. Automaton guard conditions differ from UML guard conditions because they are associated with actions instead of transitions.

The toolkit provides the abstract class DSEGuardCondition as a parent class for guard conditions.

The toolkit externalizes a guard condition using a tag that has its name defined in the toolkit configuration file. For example, if the tags collection in the file contains the <field id="ConditionTag1" value="aClass" /> definition, the tag to externalize the action is <ConditionTag1>.