Undo / Redo

muxd can undo and redo file changes made by the agent, using git under the hood.

Prerequisites

You must be working inside a git repository. If you're not in a git repo, /undo and /redo will print an error.
Git must be installed and available on your PATH.

How It Works

Before each agent turn that involves tool calls, muxd creates a checkpoint: a snapshot of your working tree at that point in time.

Under the hood:

git stash create --include-untracked is run to produce a commit object that captures the full state of the working tree (both tracked changes and untracked files), without actually modifying the stash list or your working tree.
The resulting SHA is stored as a hidden git ref at refs/muxd/<session-prefix>/<turn-number> so it won't be garbage collected.
Checkpoints are kept on an in-memory stack.

Usage

Undo

/undo

Restores your working tree to the state before the last agent turn:

Saves the current working tree state so /redo can bring it back.
Resets the working tree to match HEAD (git checkout -- . + git clean -fd).
If the checkpoint recorded a dirty tree, applies the checkpoint stash to restore those changes.

You can run /undo multiple times to walk back through previous turns.

Redo

/redo

Re-applies the last undone change. Only available after an /undo. The redo stack is cleared whenever the agent runs a new turn, so you can only redo changes that haven't been superseded by new agent work.

Multiple Undo / Redo

Checkpoints and redo states are stacks. Each /undo pops from the checkpoint stack and pushes onto the redo stack. Each /redo does the reverse. You can undo and redo as many times as there are entries.

Turn 1: agent edits file A        checkpoint 1
Turn 2: agent edits file B        checkpoint 2
Turn 3: agent edits file C        checkpoint 3

/undo  → working tree restored to checkpoint 3 (before turn 3)
/undo  → working tree restored to checkpoint 2 (before turn 2)
/redo  → working tree restored to after turn 2

Edge Cases

Situation	Behavior
Not in a git repo	`/undo` and `/redo` print an error
No checkpoints	"/undo" prints "Nothing to undo"
No redo states	"/redo" prints "Nothing to redo"
Agent is running	Cannot undo/redo while the agent loop is active
Clean working tree at checkpoint	Checkpoint records `isClean = true` with no stash SHA; restore just resets to HEAD
Checkpoint creation fails	A warning is printed but tool execution continues
New agent turn after undo	The redo stack is cleared

Cleanup

When you start a new session with /new, all checkpoint refs for the previous session are deleted from .git/refs/muxd/. This prevents accumulation of hidden refs over time.