Checkpoints
Undo what Hull changed by reverting your files and conversation to an earlier message.
Hull snapshots your files as it works, so you can roll a session back to the point before any message. Try an approach, and if you don't like it, revert and ask for something different.
Checkpoints are on by default. They need Git installed. If Git isn't available or the folder isn't a Git repository, Hull skips checkpoints automatically.
Revert to an earlier message
Hover over one of your messages and choose Revert to this message. Your files go back to how they were just before you sent it. In the Review panel you can also undo the changes to a single file. See Review and ship.
You can't revert while the agent is working. Interrupt the turn first.
Reverting is reversible until you send a new message. Revert and redo freely to compare approaches.
How it works
- Before and after each model step, Hull records a snapshot of your working tree in a separate Git repository stored in Hull's data directory (for example
~/.local/share/hull/snapshot/on Linux). Your project's own.githistory is never touched. - A single message can produce several steps, but you revert per message. Reverting undoes every change Hull made in response to it.
- Files that Hull created are deleted on revert. Files ignored by
.gitignorearen't snapshotted. - Each worktree, including Agent Manager worktrees, gets its own snapshot repository.
- Hull prunes old snapshot data in the background, removing unreachable snapshots older than 7 days.
Limits
- Only changes made by Hull during a session are tracked. Your own edits and changes by other tools aren't checkpointed, and reverting can overwrite them.
- Very large binary files can slow snapshots down.
Turn checkpoints off
Use Settings › Checkpoints in Desktop or VS Code, or set snapshot in hull.jsonc:
{
"snapshot": false
}With checkpoints off, reverting still rewinds the conversation, but your files stay as they are.
Clean up old sessions
Session history grows over time. Hull can delete old sessions on a schedule. It's off by default.
In VS Code, open Settings › Checkpoints, turn on Enable automatic session cleanup, and set Keep sessions for (days) (30 by default). Run Cleanup Now runs it immediately after asking you to confirm.
The policy is machine-wide: it applies to every project and every Hull client on this computer. Cleanup skips sessions that are busy or were written to in the last hour, and keeps an old session while a recent fork of it still exists.
Cleanup permanently deletes sessions and their conversation history across every project on this machine. Choose a retention period that fits how you work.