Note: Beginning October 1, 2017, references to @contact inside the "Send a message to someone else" action will be refer to the active contact in the run, not the recipient for the message. To reference the details for the recipient, instead start that contact in a flow and use the normal Send Message action with @contact.
There are two ways to reference contacts and their fields within a workflow:
@contact - references the contact receiving the message. In most cases, this is the active contact - the person whose responses are being handled by the workflow. When using the Send a Message to Someone Else action, @contact refers to the contact or group of contacts to which the message is being sent.
@step.contact - references the contact who sent the last message handled by the workflow. In most cases, this is also the active contact. When using the Send an SMS Response action, @step.contact and @contact are the same contact. When using the Send a Message to Someone Else action, @step.contact refers to the contact who will reach that action.
Here's an example:
Since the message created by the Send a Message to Someone Else action is being sent to Edward, @contact.first_name will be replaced with Edward's first name. @step.contact.name and @step.contact.tel will be replaced with the name and phone number of the patient that just registered via the workflow containing the Send a Message to Someone Else action.
For more information about variables, visit the Flow Variable Reference.