That would be this post.
http://discourse.stonehearth.net/t/is-it-possible-to-override-a-service/10447/2
Pretty outdated on some parts, as is expected of a 18 month old post, but the general gist still applies. Jelly is dead, as it’s outlived its usefulness and most of the hacks it did are now (semi-)official/usable APIs.
The basic point still stands, however: It’s officially unsupported/frowned upon, it’s going to break at random times (basically, whenever something changes). If you truly do need to change something, and there’s no way to avoid it, try monkey patching the function (replacing it with one you’ve written). Ideally, you can call the old function and just do your stuff before/after; but that’s not always possible. Keep whatever change you make to an extern system as minimal as possible - the less code you touch, the less code can break.
On the topic, however, I’m not sure if you actually need touch lua for this case at all. I believe, and I might am mistaken, that this is defined by task groups, which are all JSON. A task group has a list of actions it covers. So you would need to override parts of the task group for the player, add a few new ones, make some adjustments to the GUI (probably)… I don’t think changes to lua are necessary, but it’s possible that whatever schedules the task uses a hardcoded string that might not work for you.