A method and system are described for validating process models. A process semantic model including a semantic directed graph including nodes associated with tasks and edges associated with a direction of flow of execution of the tasks may be obtained. Edges entering nodes include annotations including precondition semantic indicators associated with the entering edges and edges exiting nodes include annotations including postcondition semantic indicators associated with the exiting edges. The process semantic model may be traversed to determine a flow of execution of activities associated with the tasks based on visiting the nodes based on a depth-first traversal. A validity of execution associated with a flow of execution of the activities associated with the tasks may be determined based on checking a validity of execution status based on a semantic processing of one or more semantic annotation indicators associated with the precondition semantic indicators and the postcondition semantic indicators.