The suite keeps saved copies of each world, takes one before anything risky, and puts one back with a click.
A world is the thing a player can least afford to lose, so saved copies became part of the suite itself. A saved copy is a row that pins the stored pieces of the world it copies, so nothing is duplicated and nothing it pins can be swept away. A copy is taken before a seed or generator change, before a chunk is dropped, before a save slot is deleted and before a new game, and the change is refused if the copy fails.
Copies are also taken every 30 minutes when the world has changed, and kept on a schedule of a day, two weeks and 90 days. In the game, the world panel has Keep a copy now and a list of copies to restore, and a restore first keeps a copy of what is there, so a restore can be undone. The Builder in the suite has the same Saved copies panel, and the suite's own tools can list, take, restore and verify copies.
Still to do: holding the page's own autosave while a copy is restored from outside, a restore test on a two-generation world, and the city's rows covered by the same copies.
Live on our demo host since live rebuild 25 on 17 October 2026. The demo host is our own test server; since live rebuild 26 a shared world on it can also be joined from a link over the internet.
Every wave closes with a play test on the build machine in the browser: a scripted story test that plays the new loop end to end and reloads the world to check it came back exactly, the older waves' story tests run again on the merged build, the engine's unit tests, and a 15-minute soak that records frame rate, faults and world memory. The numbers above come from those runs, as written in our build tracker.