1. A system for reconstructing the state of an application, the system comprising one or more hardware computing devices configured to execute: one or more activity modules configured to execute an action of a workflow definition; and a workflow decision module configured to: receive a first workflow history record from a data store, wherein the first workflow history record comprises data related to an event of a workflow application execution; determine a first activity module to execute based at least in part on the first workflow history record, wherein determining the first activity module alters the program state of the workflow decision module; create a first command to execute the first activity module; issue the first command; determine whether the first command completed successfully; if the first command completes successfully: replay the determination of the first activity module to execute; and recreate the first command; receive a second workflow history record from the data store; and in response to receiving the second workflow history record: disregard the recreated first command, wherein disregarding the recreated first command comprises preventing re-execution of the first command; determine a second activity module to execute based at least in part on the altered program state; create a second command to execute the second activity module; and issue the second command.