Keep / Undo for Claude Code

Review every change Claude Code makes to your files and decide, hunk by hunk, whether to Keep it or Undo it — the same review loop GitHub Copilot gives you for its own edits.

Unofficial. This is a community project. It is not affiliated with, endorsed by, or sponsored by Anthropic. Claude and Claude Code are trademarks of Anthropic, PBC.

Why

Claude Code edits files directly on disk. That is fast, but it leaves you without the "here is what changed, accept or reject it" step you get from an IDE-integrated assistant. This extension adds that step back — in the editor you are already looking at, without a diff tab.

Keep folds the change into the recorded baseline (the file stays as Claude wrote it). Undo rewrites the file back to the baseline. Either way, once baseline and file agree, the file leaves the review queue.

Highlights

• Review in place. Coloured change bars in the real editor gutter; click one and VS Code's Quick Diff widget opens inline with Keep and Undo in its toolbar. Inline comment threads are available as an alternative rendering.
• Keyboard loop. Ctrl+Alt+N / Ctrl+Alt+P to walk the changes, Ctrl+Alt+K / Ctrl+Alt+U to keep or undo the one under the caret, or Ctrl+. / Cmd+. for the same two actions as Quick Fixes.
• A pending queue you cannot lose track of. ✳ badges in the Explorer, a status bar count, a Claude: Changes to Review tree expandable down to individual hunks, and a Source Control entry — each one switchable.
• One pass over everything. Review All Claude Changes opens every pending file in a single Multi Diff Editor tab, with Keep All / Undo All at hand.
• Undo is reversible. Every destructive action is snapshotted, lands on the editor's undo stack, and is confirmed by a notification with a Restore button. A change that moved since the button was drawn is refused, never applied to whatever now occupies that position.
• Files you can keep out of it. A .keepundoignore in the project root, with the syntax you already know from .gitignore. An ignored file is not detected, not queued, and — because the rule is enforced inside the hook too — never read or copied aside. That last part is the point for a .env.
• Shell commands too. Claude does not only use its edit tools: it runs sed -i, redirects into a file, moves things, runs a formatter or a code generator. Those changes are reviewed like any other — a file the command created can be undone away, and one it modified is restored to what it held before, recovered from Git or from a copy taken beforehand.
• Zero-config, or exact. It works from the session transcript alone — reading Claude Code's own pre-edit copy of a file where there is one, including the files a subagent changed — and installing the Claude Code hooks adds precise real-time baselines and full coverage.
• Fully local, stable API only. No network calls, no telemetry, no account, no proposed APIs. State survives a reload and lives outside your repository.

📖 Full reference → — every surface, setting and command, how change detection works, the known limitations, and how to build it.

Requirements

VS Code ^1.90.0 · Node.js >= 18 on your PATH (the hook script needs it) · Claude Code with PreToolUse/PostToolUse hook support · a workspace folder open.

Installation

Search for Keep / Undo for Claude Code in the Extensions view (Ctrl+Shift+X / Cmd+Shift+X), or:

code --install-extension FedeFluork.claude-keep-undo

Quick start

1. Open a project where you use Claude Code.
2. On first activation the extension offers to install its Claude Code hooks. Accept for precise, real-time detection — or choose Transcript only and it works with zero configuration.
3. Let Claude edit some files. They pick up an ✳ badge in the Explorer, coloured bars in the gutter, and an entry under Claude: Changes to Review.
4. Click a gutter bar and press Keep or Undo in the widget that opens — or review from the keyboard, or from a diff tab.
5. Finish with Keep All / Undo All from the editor title bar, the changes view toolbar, or the Source Control title bar.

Too much on screen, or not enough? Claude Keep/Undo: Settings and Setup turns every surface on or off, with three presets — Minimal, Recommended, Everything. See the settings reference for the full list.

How it works

Two complementary detection mechanisms, both on by default:

• Claude Code hooks — PreToolUse captures the file before Claude writes, PostToolUse publishes it as a baseline once the write lands. Exact, and never blocks a tool call.
• The session transcript — a zero-config fallback that reconstructs the pre-Claude content by reverse-applying the recorded edits, then proves the result by replaying them forward against the file on disk. Where the answer cannot be established exactly the file is listed as not reviewable instead of shown against a guessed baseline, so coverage is partial by design.

Baselines and recovery snapshots go into VS Code's global storage (globalStorage/folders/<hash>), keyed by folder path — never into your repository. The same repo opened alone or in another window keeps the same review queue. How change detection works →

Known limitations

The big ones — the full list is in the reference, and each one is a constraint of VS Code's stable extension API:

• It is not Copilot's exact widget: phantom deleted lines live in VS Code core and are not exposed to extensions at all.
• In a Git repository you may see two sets of gutter bars, and a second Claude Changes entry appears in the Source Control view.
• Without the hooks, an edit whose original cannot be established exactly is listed with an explanation rather than reviewed.
• Reviewing what a shell command changed needs the hooks and a Git repository. Outside one, or with Git unavailable, those changes are not detected — the extension says so once instead of leaving the queue quietly empty. Claude's ordinary edit tools are unaffected either way.
• UTF-8 text only. Multi-root workspaces are supported: each folder has its own review queue, and state is keyed by folder so the same repo in another window keeps its pending reviews.

Privacy

No network requests, no telemetry, nothing sent anywhere. The extension reads your workspace files and your local Claude Code session transcripts, and writes baselines and recovery snapshots into VS Code's global storage (globalStorage/folders/<hash>), keyed by folder path — outside your repository. All of it stays on your machine. Anything listed in .keepundoignore is not read at all.

Development

npm install
npm run compile     # or: npm run watch
npm test            # unit + integration
npm run package     # builds claude-keep-undo-<version>.vsix

Press F5 (Run Extension) for an Extension Development Host. Details, including the project layout, are in the reference.

Contributing

Issues and pull requests are welcome at github.com/FedeFluork/claude-keep-undo. Please keep changes dependency-free — the extension intentionally ships with no runtime dependencies.

License

MIT © FedeFluork