# dsh-rewind

Conversation rewind for DeepSeek Harness: **rewind the conversation to any earlier user message in one click, in the same window**.<br />
No new branch, no window switch, with optional workspace-file restore — the full Claude Code `/rewind` semantics.

English | [中文](README.md)

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![Rewind to an earlier message, with optional file restore](docs/preview.svg)

A deliberately focused plugin with one job: **rewind to any user message, no matter how far back, in place** — and conveniently **restore the files it changed** along the way.

- **In-place rewind, no new session** — the target message and everything after it (replies, tool calls) are withdrawn from the model context *and* the rendered transcript, and the target's text is filled back into the composer for editing and re-sending. It all happens inside the original session: no new branch, no leftover copy.
- **Conversation and files rewind together** — Claude Code-aligned behavior: files edited by the write tools are tracked and restored by the same rewind, and external changes to already-tracked files are restorable too. **Partial tracking, before-write backup, store only on change**, with no git dependency.
- **Safety guarantees** — the session log only ever appends rewind markers and is never deleted or rewritten; file backup and restore are hardened; tests are comprehensive, and maintenance continues across DSH upgrades. Security model: [SECURITY.md](SECURITY.md).

## Preview

Every user message carries a **↶ rewind** button in its action row. Clicking it opens a mode-selection popover — "**rewind conversation only**" or "**rewind conversation and files**", the latter showing the file-change list for confirmation first. You can also pick and rewind conveniently via the **`/rewind` and `/undo` commands**.

<table>
  <tr>
    <td align="center"><img src="assets/screenshots/rewind-button.png" width="440" alt="Per-message ↶ rewind button"><br><sub>Per-message ↶ rewind button</sub></td>
    <td align="center"><img src="assets/screenshots/mode-popover.png" width="440" alt="Mode-selection popover"><br><sub>Mode-selection popover</sub></td>
  </tr>
  <tr>
    <td align="center"><img src="assets/screenshots/impact-list.png" width="440" alt="Impact list"><br><sub>"Conversation and files" impact list</sub></td>
    <td align="center"><img src="assets/screenshots/rewind-candidates.png" width="440" alt="/rewind candidate picker"><br><sub>/rewind candidate picker</sub></td>
  </tr>
</table>

## Install

**Command line**:

```sh
dsh plugin --profile <name> add dsh-rewind-plugin
```

**Graphical interface**: the **Plugins** page in the sidebar → **Add plugin** → enter `dsh-rewind-plugin` → install → restart DSH.

<img src="assets/screenshots/add-plugin.png" width="600" alt="Add plugin dialog: enter dsh-rewind-plugin in the field"><br>

The default install is `latest`, which targets the latest stable DSH release. If you are on an older or alpha DSH version, find the matching plugin version on the [Releases](https://github.com/SiriLee/dsh-rewind/releases) page and install that version explicitly.

> [!WARNING]
> The npm name `dsh-rewind` belongs to another author's package — install with `dsh-rewind-plugin`.

## Usage

1. Find the user message you want to rewind to in the conversation, or type `/rewind` (or its alias `/undo`) to open the candidate picker.
2. **Select it.** A small popover offers the two modes — "conversation only" or "conversation and files".
3. The rewind takes effect immediately: the conversation returns to how it looked at the target message, and the target message's text is filled back into the composer — edit and re-send.

**Keyboard**: both the candidate picker and the mode popover support ↑↓ to move, Enter to confirm, Esc to cancel/back.

<details>
<summary><b>Edge notes</b></summary>

- **The withdrawn content is preserved** — it stays in the session log and can be inspected in the **Trajectory** panel; you can also disable the plugin to show it again (display only).
- **A rewind cannot be undone in place** — to carry the content forward, first disable the plugin so the withdrawn content shows again, then click **Branch into a new conversation** on the message just before the rewind; the new conversation's context will include it.
- **Interruptions rewind too** — a `steering` message the model hasn't read yet is also a valid rewind target, and withdrawing it does not interrupt the current run.
- **Rewinding a read message interrupts the running turn** — to ensure the rewind runs safely.

</details>

## Snapshot management

**Snapshot backups** are on by default: they power file restore and can be
switched off in this plugin's configuration card. When off, no new snapshots
are created; file changes made while off cannot be restored. Snapshots (the
before-write backups) are stored under `<dsh home>/rewind-snapshots/`
(the default is `~/.dsh/rewind-snapshots/`).
**Deleting that directory manually** only clears the file backups (chat rewinds are
unaffected); the plugin can rebuild that directory automatically.

A **snapshot auto-cleanup** (off by default) removes the snapshot directories of
long-inactive sessions, leaving the active session and chat log untouched. Configure
and review it on the **Plugins** page, in this plugin's configuration card (the
auto-cleanup switch and the idle-day cutoff), or use the
`/snapshot-auto-cleanup` command to **view, configure, and run** it. See:
[Snapshot auto-cleanup](docs/snapshot-auto-cleanup.md).

<img src="assets/screenshots/plugin-setting.png" alt="Plugin configuration card: snapshot backups and auto cleanup" width="600">

## Uninstall

```sh
# Uninstall the plugin
dsh plugin --profile <name> remove dsh-rewind-plugin

# To also delete local data
rm -rf <dsh home>/rewind-snapshots
rm <dsh home>/snapshot-cleanup-last-sweep.json
```

The plugin's configuration entries are stored in the current Profile's config
file `cordis.patch.yml`. To clean up completely, delete the corresponding entries
manually.

## What this plugin changes

Compared with the default behavior:

| Dimension | Default behavior | This plugin |
| --- | --- | --- |
| Conversation rewind | Branch into a new conversation | **In-place rewind** — no new session branch, no window switch, no leftover session copies, and rewinding is more convenient |
| File restore | Manual restore / Git management | **One-click restore** — lightweight before-write backups; optionally restore files together with the conversation, fitting agent workflows |
| Restore dependencies | Often needs a Git repository or a full snapshot engine | **None** — no Git repository and no code project required; works in any directory |

## How it works

The whole design rests on two principles, simple but deliberate: **the conversation half "masks, never deletes"**, using DSH's native "hide + replace" mechanism; **the file half "partial tracking, lightweight before-write backup"**, following Claude Code's checkpoint semantics.

### 1. Conversation rewind: a single "mask", not a delete

`append-only` is a hard rule: the session log only grows and is never rewritten — the foundation of auditability and privacy. A rewind never touches history; it makes a single move: append **one "empty message" marker** to the end of the log and use it to "mask + replace" the target message and everything after it, so the model and the UI see only what came before it.

- **One and the same log** — the append happens only in the current session's log: no new session, no new branch, so no residue or copy is left behind;
- **The marker is canonical** — the same "hide + replace" as the official `/compact`: `/compact` compresses a span of history into a summary, while `/rewind` swaps in an "empty message" marker. Because it is canonical, DSH's log replay, compaction, and resume preflight all recognize it and never mistake it for a real message;
- **The replacement is imperceptible** — the model ignores the marker, with no effect (verified empirically). Together with the plugin's UI handling, what you and the model see is exactly how the conversation looked at the target;
- **Content is preserved** — because this is "masking, not deleting", the withdrawn content stays in the log — auditable, traceable, and in principle manually recoverable.

> **Design highlight**: the entire conversation rewind is **a single append**. It's deterministic, auditable, and — because the log was never broken — a "clean" time-travel. Minimal action, complete semantics.

### 2. File restore: lightweight checkpointing, "before-write backup"

The file half follows Claude Code's checkpoint semantics — **partial tracking + before-write backup, plus a re-scan of tracked files at each message**, not a whole-tree snapshot. This trade-off saves space while still covering external changes to tracked files:

- **Before-write backup**: tracks only the write-class tools (`write`, `edit`) — backs up the original content before a write and records/tracks the files it touches; it never backs up the whole workspace, so it's lightweight; **a single file that is too large is not backed up**.
- **External changes count too**: at every user-message boundary the plugin re-checks all tracked files — external changes such as a command run or a manual edit are recorded as well and restored by a later rewind. "Lightweight" but not "incomplete".
- **Unchanged-not-recorded**: an entry is written only when something changed — at the message-boundary re-check, an unchanged file is never backed up (no record); at before-write time, when the new content matches the path's prior record, only a **link to it** (`ref`) is stored instead of a copy.
- **Accurate restore**: backups are the sole standard, checked against the real disk — **only files that actually differ are touched**. Backups are stored byte for byte, so the restored result matches the backups exactly, with no "ghost impact". Coverage is bounded by design: [File-rewind tracking boundary](docs/compat/tracking-boundary.md).
- **Safety and integrity**: paths are sanitized so nothing ever escapes the backup root; symlinks / hard links are skipped so one restore can't clobber another name of the same file; a per-file failure never aborts the pass; backups and the restore journal are written atomically and kept across restarts, so a half-applied restore after a crash can be continued or rolled back.

> **Design highlight**: this checkpoint's light footprint comes from **recording only what was actually touched and really changed** — before-write backup makes it restorable, unchanged-not-recorded and content-as-link drop the repetition; only the files that differ are touched at restore time.

## Scope and division of labour

This plugin deliberately stays lightweight and focused on one thing — "conversation rewind". The following are **out of its scope**, and each has a better owner (see [design boundaries](docs/boundaries.md)):

- **Whole-tree / Git-level snapshots** — only write-class tool edits plus external changes to already-tracked files are backed up; files never touched by a tool are not restored. Workspace history — any file, any moment — belongs to Git; the agent already uses it, and the plugin does not rebuild that layer. For a worktree-level full snapshot rollback, use Git or the snapshot tool the project already uses.
- **Subagent edits** — not tracked, and no rewind inside a subagent session (same as Claude Code): a subagent runs its own session, so its backups could never be restored by a rewind of the parent session, and none are kept for one.
- **Fork / branch rewind** — DSH already provides this ("branch in new chat"); no need to reinvent the wheel.

## Compatibility

- Node.js `>=24.9.0`.
- Supported DSH versions are declared by `package.json` `engines.dsh`.
- Compatibility definition, verification method, and version alignment: see [docs/compat/audit.md](docs/compat/audit.md).

> [!WARNING]
> This project and DeepSeek Harness are both in developer preview. Pin exact
> versions in reproducible environments and review the behavior notes above.

## Known limitations

1. **Turn navigation keeps rewound turns** — the right-side turn navigation keeps an "unloaded" tick for each rewound turn, and hovering previews the withdrawn content. Only a display difference; no functional impact.
2. **A far rewind may show a blank transcript** — when the target predates the loaded history, the conversation area goes blank; click **Load earlier** to page back until the history appears.

> [!NOTE]
> Browser diagnostics are available; see [Browser diagnostics](docs/compat/diagnostics.md).

## Security

This plugin only appends rewind-marker events to the session log; it never deletes or rewrites logged history. Workspace files are written only when you choose "conversation and files"; backups are stored under `<dsh home>/rewind-snapshots/`; restores draw only from those backups. It never touches your git repository, makes no network requests, and accesses no credentials. For sessions you've left inactive for a long time, a snapshot auto-cleanup (off by default) can remove their snapshot directory in whole, leaving the active session and the chat log untouched. Full security model: [SECURITY.md](SECURITY.md).

## Development

```sh
npm install            # devDeps from the npm registry
npm run check          # one-shot full gate: typecheck + test + build + verify:host + pack --dry-run
npm run typecheck      # tsc on all three surfaces (host + client + client-test)
npm test               # vitest: all unit and compatibility suites
npm run build          # esbuild: lib/index.js (host ESM) + lib/client.js (loader closure) + .d.ts
node scripts/verify-host.mjs   # end-to-end verification of the built artifact
```

`prepack` runs the full build, so `npm pack` / `npm publish` always ship a complete `lib/`. Install from npm or a packed tarball — a git checkout has no built `lib/`.

Maintainers: the source layout and architecture are in [docs/architecture.md](docs/architecture.md); the harness interface reference is in [docs/harness-reference.md](docs/harness-reference.md).

Contributing guide: [CONTRIBUTING.md](CONTRIBUTING.md).

## Release

Releases go out through GitHub Actions Trusted Publishing (OIDC, no stored `NPM_TOKEN`): push a `v<version>` tag and CI publishes with Sigstore provenance.

```sh
npm version patch && git push origin <branch> --tags
```

One-time npm-side setup and the full workflow details: [docs/release/release.md](docs/release/release.md).

## License

[MIT](LICENSE)
