@kmiyh/pi-undo-redo

Warning: this extension is currently in testing mode and should be treated as experimental.

@kmiyh/pi-undo-redo is a Pi extension that adds reliable, branch-aware /undo and /redo commands for file changes made by the agent.

It does not automatically restore or roll back files just because you move around the /tree. Instead, /tree only changes which branch-local undo/redo history is active. Actual file restoration happens when you explicitly run /undo or /redo.

What this extension does

• adds /undo
• adds /redo
• tracks file mutations made through Pi's built-in edit, write, and bash tools
• groups changes by one completed agent run
• shows current undo/redo availability in a small status widget above the editor
• keeps undo/redo history local to the current /tree branch
• can ask whether to sync tracked files after switching branches when the workspace diverges
• rolls back partially applied restore attempts on failure
• persists history across restarts and /reload
• cleans up old snapshot blobs automatically

Installation

pi install npm:@kmiyh/pi-undo-redo

How it works

1. One step = one finished agent run

A single user request can trigger several tool calls.

For example, if Pi:

• edits src/app.ts
• writes src/app.css
• edits src/app.ts again

all of that is stored as one undo step.

That means:

• one /undo reverts the whole step
• one /redo reapplies the whole step

This keeps the workspace consistent instead of undoing files one by one.

2. It stores snapshots before and after changes

For every tracked file mutation, the extension stores:

• the file state before the change
• the file state after the change

Those snapshots are saved outside the session JSONL, while the session stores only the step/action metadata. This keeps history persistent without bloating the session file.

3. Undo/redo is branch-aware

Undo/redo history is derived from the current session branch.

If you navigate with /tree:

• the active undo/redo stack switches to the selected branch
• /tree itself does not perform undo or redo for you
• if tracked files do not match the selected branch, the extension can ask whether it should sync tracked files to that branch

So /redo does not jump between branches. Branch changes still happen through /tree, while actual undo/redo restoration still happens through /undo and /redo.

4. Undo/redo restores tracked files exactly

When you run /undo or /redo, the extension restores the tracked files to the recorded snapshot for that step.

That means manual edits, manual deletions, manual moves, manual renames, and manual replacements in those tracked files are discarded by the restore, so the workspace really returns to the selected undo/redo state.

In other words, undo/redo always reapplies the extension's tracked history for those files instead of trying to preserve later manual changes.

5. It shows lightweight status in the UI

Above the editor, the extension shows:

• how many undo steps are available
• how many redo steps are available
• a hint that F8 opens the undo/redo files window

This keeps the status line short while still surfacing the important actions.

6. It can show undo and redo files side by side

The extension can open a small modal that shows both:

• the current undo step
• the current redo step

They are displayed side by side, and each side groups files as:

• Added
• Modified
• Deleted

You can open it with:

• F8

Current scope

This version tracks file changes made through:

• edit
• write
• agent-driven bash

It does not provide full undo coverage for:

• external tools run outside Pi
• unrelated manual files that were never part of tracked history
• third-party mutating tools outside Pi

Automatic behaviors

Automatic branch sync prompt

After /tree navigation, if the tracked workspace does not match the selected branch, the extension asks whether it should sync tracked files now.

Automatic snapshot cleanup

Snapshot garbage collection runs automatically:

• after new steps are recorded, when internal blob count or blob size thresholds are exceeded
• on session start as a rare fallback if cleanup has not run for a long time

Local development

npm install
npm run typecheck
pi -e ./src/index.ts

License

MIT