Execution systems for augmenting legacy user interfaces include a memory, one or more input/output device, and one or more processors coupled to the memory and the one or more input/output devices. The one or more processors are configured to load a workflow described according to a workflow structure, the workflow structure describing subprocesses of the workflow, routings between the subprocesses, and actions that make up the subprocesses; connect to a legacy user interface based on the workflow; receive a message from the legacy user interface; determine a subprocess for responding to the message based on the workflow; and perform one or more actions of the determined subprocess to respond to the message. In some embodiments, performing the one or more actions includes presenting information from the message to an operator, soliciting input from the operator, and sending a response to the legacy user interface based on the input.