I think (maybe I’m wrong) that your graph searches correspond to diffing single lists and you can have an expensive diagonal step to recurse into two sublists whereas the tool in this post has extra nodes for every token and extra edges for inserting/deleting delimiters. That seems to be the biggest difference to me and I guess is what you mean by it being complicated to design a good heuristic for the expanded move set. I agree it sounds complicated. I think that my guess was that bigger graphs would make things harder but that isn’t a reason for A* to fail.