[PcChip]

a world has a seed as well, so when you walked past the generated portion it would start randomly generating from that seed, which wouldn't match the portion that was sculpted

you would have to make the AI search for seeds that generate what you want at the starting point I think

[richstokes]

If the AI could understand the save file format for Minecraft, it could manipulate that

[shaewest]

There are methods to do custom generation in of itself, so should be possible for AI to write a mod in the same vein as current world generation mods.