Facebook’s open graph action links, which it introduced in May as a way for users to interact directly with timeline applications, are being tested on some mobile apps.

Sister blog Inside Facebook reported on the test, using location-based mobile app Foursquare as an example.

According to Inside Facebook, when a mobile Facebook user sees a friend’s story about a Foursquare check-in, they will see an option to “save this place,” which, when clicked, will automatically add that location to their to-do list in Foursquare (assuming they are logged into that app), without leaving the Facebook app.

This concept can be extended to any open graph app, as Inside Facebook pointed out that Spotify could include an “add to playlist” action link; Pinterest could allow users to repin items directly from the Facebook app; and Words with Friends could use the feature to incorporate links encouraging users to play with certain friends or challenge them.

Readers: Would you find it useful to be able to interact with mobile apps without having to leave the mobile Facebook environment?

Screen grab courtesy of Inside Facebook.