{"slug":"revisions","title":"Revisions and undo","summary":"Every turn that changes the project lands as one revision. Undo puts the previous one back. Parallel conversations merge instead of overwriting each other.","body":"The assistant does not rewrite the project from scratch on each message. A turn starts from one revision, edits a private copy, and merges the result when it finishes.\n\n## Undo\n\nThe latest turn that wrote files has an **Undo** button next to its changed files in the chat. Undo restores the project to the revision before that turn. You can undo a chain of turns, one at a time, newest first.\n\nA turn you stopped keeps the edits that had already landed. Those edits are part of the revision you can undo.\n\n## Two conversations at once\n\nThe plan limits how many conversations can run together. Each one works from the revision it started on.\n\n- Changes to different files merge into one new revision.\n- Different edits to the same file are kept as a conflict for you to resolve, instead of one overwriting the other.\n\n## Checks do not rewind you\n\nIf a check fails, the latest revision stays. Fix it in chat, or edit the file yourself. Undo is the only thing that drops a revision, and only when you ask for it. See [Checks](/docs/checks).","sectionSlug":"build","sectionTitle":"Build your app","updatedAt":"2026-09-23T22:51:25.250Z","previous":{"slug":"edit-the-source","title":"Edit the source"},"next":{"slug":"app-icon","title":"App name and icon"}}