What is a Command?

A Command is a requested action issued by a Worker to the Temporal Cluster after a Workflow Task Execution completes.

The action that the Cluster takes is recorded in the Workflow Execution's Event History as an Event. The Workflow Execution can await on some of the Events that come as a result from some of the Commands.

Commands are generated by the use of Workflow APIs in your code. During a Workflow Task Execution there may be several Commands that are generated. The Commands are batched and sent to the Cluster as part of the Workflow Task Execution completion request, after the Workflow Task has progressed as far as it can with the Workflow function. There will always be WorkflowTaskStarted and WorkflowTaskCompleted Events in the Event History when there is a Workflow Task Execution completion request.

Commands are described in the Command reference and are defined in the Temporal gRPC API.