A social networking system includes a mechanism for integrating user actions on objects outside of the social networking system in the social graph. External system operators include widgets that, when executed by user devices, record user interactions that correspond to a defined structure of actions and objects. Third party operators utilize a tool provided by the social networking system to define the structure of actions and objects, verb tenses of action types, and noun forms object types. External actions are recorded by the social networking system for publishing to the social graph in dynamically generated sentences formed using the structure of the actions and objects.