As of 0.2.3, if you want to export a music composition in the tracker at the PICO-8 command line, the length of export caps at 32768 music ticks, or about four minutes and thirty-two seconds. To export something longer requires doing it in real time, be that five, ten, or seventy minutes, which is a pain and is slow.

Other exporters - sprite sheet, web application, binary - have flags to change how the export works; would it be possible to do something similar with the music/SFX exporter? Number of patterns played (or number of repeats, for a looping SFX) would seem the most intuitive for the end user, and (unlike music ticks) would involve numbers of a reasonable size, but I'm not attached to any specific solution.

I second this as I want to export my song to share on discord and it's way over 8MB, saying how many times you want it to loop or patterns would be nice.