This is not a stand-alone application but an inbound Plug-in for Locale.
You can used this Plug-in to launch locale rule when you received a SMS with specific keyword or/and from specific caller.
Since version 1.6 you can also uncheck all filter and use this condition when any SMS are receive.
Notes: If in a same condition you set keyword and caller the operator used is AND.
(If OR is needed, you can used new feature in Locale 1.x. This release offer OR condition to every condition Plug-in)