1. A computer-implemented method comprising: receiving, at a supplemental indexing application, electronic content from a primary indexing application via a first message, wherein the primary indexing application and the supplemental indexing application are separate applications executing on one or more devices, wherein the electronic content comprises executable code that does not fully expose content-defining text without execution of the electronic content by the supplemental indexing application, wherein the primary indexing application is unable to execute the executable code; identifying, at the supplemental indexing application, an external interaction that occurs during execution of the electronic content, wherein the external interaction is not available from the supplemental indexing application; communicating with the primary indexing application via a second message from the supplemental indexing application requesting performance of a function by electronic content available to the primary indexing application but not available to the supplemental indexing application, to receive, at the supplemental indexing application, information associated with the external interaction, wherein the information associated with the external interaction comprises a result of a function performed by the primary indexing application on the electronic content; identifying, at the supplemental indexing application, one or more content-descriptive terms for the electronic content, wherein said identifying the one or more content-descriptive terms comprises using the information associated with the external interaction.