A system includes a development tool for adding electronically-driven effects to a dynamic user-influenced media experience. The development tool is adapted to receive first user input and second user input. The first user input defines an audio trigger corresponding to one or more words or phrases appearing in a textual transcript of an audio content stream that includes audio data to be played as part of the dynamic user-influenced media experience. The second user input defines an event that is to be executed in temporal association with an audible occurrence of the audio trigger. The development tool generates metadata based on the first user input and the second user input, and an application engine interprets the metadata as an instruction to selectively trigger execution of the event in association with the audible occurrence of the audio trigger while presenting the dynamic user-influenced media experience.