@ahm3tj4f/pi-undo

Undo/redo for pi, but this time it works. Per-message snapshots, ported from OpenCode's exact undo/redo philosophy.

Packages

Package details

extension

Install @ahm3tj4f/pi-undo from npm and Pi will load the resources declared by the package manifest.

npm repo home report

$ pi install npm:@ahm3tj4f/pi-undo

Package: @ahm3tj4f/pi-undo
Version: 0.5.0
Published: Oct 7, 2026
Downloads: 317/mo · 217/wk
Author: ahm3tj4f
License: MIT
Types: extension
Size: 72.4 KB
Dependencies: 1 dependency · 1 peer

Pi manifest JSON

{
  "extensions": [
    "./src/index.ts"
  ]
}

Security note

Pi packages can execute code and influence agent behavior. Review the source before installing third-party packages.

README

pi-undo

Undo and redo for pi. One command rolls back the last message: the conversation and the files that the message changed.

The design follows OpenCode: a snapshot of the files before and after each message, in a shadow git repository.

Commands

Command	What it does
`/undo`	Stops the agent if it runs. Shows the changes of the last message. Restores the files to their state before the message. Moves the conversation back and puts the prompt in the editor.
`/redo`	Applies the last undone message again: the files and the conversation.
`/diff`	Shows the changes that `/undo` rolls back. It does not stop a running agent.

For example, the agent edits src/app.ts and creates src/new.ts. /undo restores src/app.ts, deletes src/new.ts, and removes the message from the conversation.

Install

pi install npm:@ahm3tj4f/pi-undo

You can also install from git:

pi install git:github.com/ahm3tj4f/pi-undo

pi-undo needs git 2.31 or newer.

How it works

Each agent run gets two snapshots. pi-undo takes the first snapshot when the run starts. It takes the second snapshot when the run ends. A snapshot is a git tree in a shadow repository under ~/.pi/agent/pi-undo/snapshots/. Your own git repository never changes.

The two snapshots show which files the message changed. /undo restores all of these files. The tool that changed a file has no effect: the edit tool, a bash command, a formatter, and a subagent are all the same.

The checkpoints are part of the pi session. Undo and redo work after a restart.

Safety

Manual edits. You can change a file after the message. In that case, the undo dialog shows the file and tells you that your change will be lost. Nothing changes until you confirm.
Files outside the message. /undo never touches a file that the message did not change.
Verification. After a restore, pi-undo compares each restored file with the snapshot.
Rollback. If a restore fails, pi-undo puts every file back to its state just before the undo. Your manual edits stay.
Order. pi-undo restores the files first and moves the conversation after. If the conversation cannot move, the files go back.
Symlinks. pi-undo never writes through a symlinked directory.
Gitignored files. pi-undo snapshots files that your .gitignore ignores. A change to .env by the agent is undoable.

Configuration

pi-undo reads ~/.pi/agent/pi-undo.json. On the first run, pi-undo writes this file with the default values. Edit the file to change them. The file is the full configuration: when you remove an entry from excludeDirectories, pi-undo snapshots that path again.

{
  "excludeDirectories": ["node_modules", "dist", "build", ".venv", "..."],
  "maxFiles": 100000,
  "retentionDays": 30
}

Field	What it does
`excludeDirectories`	Gitignore patterns that pi-undo never snapshots. A plain name matches at all depths. Globs like `*/build-` and `*.tmp` work. A trailing slash matches directories only.
`maxFiles`	The largest number of new or changed files that one snapshot can add. Above this number, pi-undo skips the snapshot and shows a warning. Undo of that message can then move the conversation only.
`retentionDays`	The number of days that pi-undo keeps snapshots. After this period, undo of the message can move the conversation only.

Limits

pi-undo does not snapshot new files larger than 2 MB. It shows a warning when this occurs.
pi-undo does not snapshot nested git repositories. They have their own history.
pi-undo does not restore image attachments of a prompt to the editor.
Two pi sessions in the same directory share one snapshot store. If both sessions change the same file during one message, /undo in one session also rolls back the change of the other session.

Development

npm install
npm run typecheck
npm test

The tests use real git in temporary directories. They never touch ~/.pi.

License

MIT