Operation contract whose implementation is a Sequential Workflow. It connects a named operation request to a workflow handler: when the configured channel accepts an event for the operation, the workflow steps run deterministically and produce processor effects. This type is useful for common document-owned behavior such as submitting a request, validating inputs, building a changeset with Compute, applying it with Update Document, and emitting follow-up events. It keeps operation logic in Blue content so the operation can be inspected, versioned, hashed, and transported with the document.