Just talking to myself...
When groovy template to create content is executed, following variables is passed to template:
AlertDefinitionInterface alertdef
AlertInterface alert
ActionExecutionInfo info
Resource resource
AuthzSubject user
params.put("alertDef", alertdef);
params.put("alert", alert);
params.put("action", info);
params.put("resource", resource);
params.put("user", user);
From template we will see user object and it contains interesting fields like:
user.phoneNumber
user.emailAddress
user.sMSAddress
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There is also third way to do this which is not very good solution. If hq server is on unix, give your local OS email address to smsaddress field. This works if hq is sending emails through local sendmail. And if your script can read local mailboxes it can also send messages to your phone. This was my first idea, which is also most worst idea you can get. For obvious reasons....
To execute external scripts from groovy templates is also a bit risky business. If your external script execution blocks, it will mess up alerting framework. I guess those template executions are always queued.