I accidentally liked and commented on my fork of this notebook yesterday, so here's me just copying everything over: Sneaky! So, from what I'm seeing here, each imported notebook has its own runtime? Ah, right - each notebook is a separate *module*. In my experiments I've taken a slightly different approach: there's a second argument for forEach that allows to pass the callback context. This is where the runtime gets passed in (for _dirty). However, I'm having a hard time getting the runtime on the first try (the runtime cell needs to rerun manually): https://observablehq.com/d/e1c39d41e8e944b0 +++ end of copy +++ Anyway, I'll leave it at that for now. I ran some tests with Map.prototype.get, but still couldn't get to the runtime on first run, when importing {runtime} to another notebook.