Automated initiation and adaptation of a dialog with a user via user interface devices of a computing device of the user

Methods and apparatus directed to utilizing an automated messaging system to initiate and/or adapt a dialog with at least one user, where the dialog occurs via user interface input and output devices of at least one computing device of the user. In some of those implementations, the automated messaging system identifies at least one task associated with the user and initiates the dialog with the user based on identifying the task. The automated messaging system may initiate the dialog to provide the user with additional information related to the task and/or to determine, based on user input provided during the dialog, values for one or more parameters of the task. In some implementations, the automated messaging system may further initiate performance of the task utilizing parameters determined during the dialog.