1. A method comprising: executing a respective automated assistant client on each of at least two client computing devices communicatively coupled via one or more networks with an automated assistant, wherein the automated assistant is cloud-based and wherein the automated assistant is further communicatively coupled to a user-controlled resources engine that includes a plurality of services accessible to a plurality of users of the automated assistant, each of the plurality of users having one or more accounts with one or more of the plurality of services; receiving a voice input from one of the plurality of users at an input device of a first client computing device operated by the first user; performing automatic voice recognition on the voice input; recognizing a task request from an output of the automatic voice recognition; analyzing the task request to identify that the task request seeks access to user-controlled resources of a second user of the plurality of users, the second user being associated with a mobile second client computing device; analyzing the task request to identify a geographic constraint and a time constraint imposed by the task request; checking an access control list relating to the plurality of services of the user-controlled resources engine to determine whether the first user has appropriate access rights as regards the second user for action to be taken on at least a portion of the task request; determining that the first user has appropriate access rights as regards the second user for action to be taken on the portion of the task request; reading information from one or more accounts of the second user to which the first user has appropriate access rights including an account of the second user with a location service that makes available, upon request, a position of the second user provided by the mobile second client computing device; obtaining a current position of the second user from the account of the second user with the location service; verifying that the current position of the second user satisfies the geographic constraint; verifying that a current time satisfies the time constraint; causing the automated assistant to engage in a natural language human-to-computer dialog with the second user via the automated assistant client operating on the mobile second client computing device at the current position and the current time; and conveying the portion of the task request to the second user via an output component of the mobile second client computing device.