1. A method, comprising: examining, by one or more processors, an ongoing message exchange thread between two or more users operating two or more message exchange clients; determining, by one or more of the processors, based on the examining: a plurality of candidate service entities that are relevant to one or more terms of the message exchange thread, and at least one action associated with the candidate service entities; generating, by one or more of the processors, a prompt that is tailored to the action and the candidate service entities; incorporating, by one or more of the processors, the prompt into the message exchange thread for presentation to at least one of the users via at least one of the message exchange clients; identifying, by one or more of the processors, at least one response to the prompt, the response being provided by at least one of the users in the message exchange thread; determining, by one or more of the processors, a particular entity of the candidate service entities based on conformance of the particular entity to the response; and incorporating, by one or more of the processors based on determining the particular entity, a graphical element into the message exchange thread for presentation to each of the two or more users, the graphical element identifying one or more properties of the particular entity; by one or more of the processors subsequent to incorporating the graphical element into the message exchange thread, identifying further user interface input that solicits performance of the action with the particular entity, the further user interface input provided by at least one of the users in the message exchange thread; by one or more of the processors in response to the further user interface input, determining, through communication with one or more computing systems in attempting performance of the action, that at least one criterion for the action is not achievable for the particular entity, the at least one criterion being specified by one or more of the users in the message exchange thread; by one or more of the processors in response to determining that the at least one criterion is not achievable for the particular entity, determining that the at least one criterion is achievable for an additional particular entity of the candidate service entities; and by one or more of the processors in response to determining that the at least one criterion is achievable for the additional particular entity, incorporating an additional graphical element into the message exchange thread for presentation to each of the two or more users, the additional graphical element identifying one or more properties of the additional particular entity.