dsh-two-pane-sidebar

A persistent plugin rail for DeepSeek Harness — it moves the plugin navigation out of the main sidebar into a slim column of its own, leaving the sidebar to do one job: new session, workspaces, sessions.

┌──────────────┬────────────────────┬─────────────────────┐
│  plugin rail │  sidebar           │  conversation       │
│  (52/208 px) │  new session       │                     │
│  ──────────  │  workspaces        │                     │
│  ▣ plugins   │    search          │                     │
│  ▣ market    │    ▣ workspace A   │                     │
│  ▣ tasks     │    ▣ workspace B   │                     │
│  ▣ skills    │  sessions          │                     │
│  …           │                    │                     │
└──────────────┴────────────────────┴─────────────────────┘
        ↑ drawn by this plugin        ↑ untouched, shipped SidebarRoot

The rail is data-driven: it renders whatever is registered in the host's sidebar.panellist slot ({ id, order, label, component }). Install a plugin that registers a navigation entry and it shows up here automatically — no code change, no configuration. Unregister it and it disappears.

This plugin is client-only. It installs no Host behaviour, makes no network requests, sends no telemetry, and never touches your sessions or workspaces. Its entire state is one localStorage key.

Requirements

Harness	DSH Desktop / Web 0.2.1-rc.2 (Windows, macOS, Linux)
Runtime	none — plain ESM, no build step, no dependencies
Compatibility	declares engines.dsh = ">=0.2.1-rc.2 <0.3.0", see Compatibility

Install

Pick one. All three go through the Host's plugin manager, which writes the profile manifest, runs pnpm add, and applies the bundle patch.

# 1. registry — not on npm yet, the name is reserved for a future release:
#    plugin_manager install_bundle target=@a-meng-e/dsh-two-pane-sidebar@0.2.0

# 2. release tarball — no npm account, a fixed immutable artifact
plugin_manager install_bundle target=https://github.com/A-Meng-E/dsh-two-pane-sidebar/releases/download/v0.2.0/dsh-two-pane-sidebar-0.2.0.tgz

# 3. straight from git
plugin_manager install_bundle target=git+https://github.com/A-Meng-E/dsh-two-pane-sidebar.git

Then restart the app (profile changes are not hot-reloaded) and reload the page.

The spec is forwarded to pnpm add, so file: / link: local paths work too — that is how development installs work.

Use

• Click a row to open that plugin's panel; the active row is highlighted with a left bar.
• Hover a row in the narrow rail for a themed tooltip.
• The arrow button at the bottom switches between 52 px (icons only) and 208 px (icons + labels). It is in the same place in both widths, so it never jumps.
• The choice is stored in localStorage["dsh.two-pane-sidebar.v2"] and survives restarts.
• prefers-reduced-motion disables the width transition.

There is no mode to configure: the rail is always on, and the sidebar always keeps its own width (whatever you last dragged it to). The rail reserves its space with a left padding on the frame, so the conversation column gives up 52 px — the sidebar does not shrink.

Uninstall

plugin_manager remove_bundle target=dsh-two-pane-sidebar

Or quit the app first, then delete the dsh-two-pane-sidebar line from ~/.dsh/profiles/<profile>/package.json and its entry from dsh.profile.bundles. Verify before editing: editing profile files while the app is running can trip a hot-reload race in unrelated built-in plugins.

Nothing is left behind except the localStorage key, which is inert.

How it works

client.js is the whole thing (~670 lines, no dependencies):

1. registers a component into the host's frame-level shell.overlay slot;
2. locates the layout frame ([data-shell-overlay].parentElement) and sets padding-left on it to reserve the rail's column — this is the only imperative DOM contact point, and it is reverted by the effect cleanup;
3. reads sidebar.panellist through slots.entriesOfSlot(), subscribes to slot and locale changes, and renders one row per entry;
4. renders each entry's own icon component directly (the host only injects renderSlot into entries that declare children, which this one does not), behind an error boundary so one broken icon cannot take the rail down;
5. copies the computed background/texture/text colour of the native sidebar column onto the rail, so third-party skins apply without any per-skin code;
6. hides the now-duplicated navigation list inside the native sidebar with one CSS rule.

Every host interaction is guarded: a missing service, slot, or DOM node degrades the rail instead of breaking app boot.

Compatibility

This plugin deliberately depends on host internals, all of which can change between Harness releases:

Depends on	Used for
shell.overlay slot	mounting the rail
sidebar.panellist slot + entry shape {id, order, label, component}	the rail's content
[data-shell-overlay] and its parent frame	reserving the column
nav[class*="_panelList"] (hashed class)	hiding the duplicated nav list
[class*="sidebarCol"] / [class*="_root"] (hashed class)	following the active skin
@deepseek-ai/dsh-client-ui-primitives → Tooltip	themed tooltips
ctx.layout.selectPanel(id)	opening a panel on click

If an update breaks one of them the rail degrades or disappears; it does not corrupt data. The checklist for re-verifying after a Harness upgrade is in docs/troubleshooting.md.

Known limits

• Not a native second view container: the rail lives in the overlay layer and reserves space with padding. There is no draggable splitter, and the rail has exactly two widths.
• The conversation column loses 52 px; the host's viewport < 1024 "narrow window" threshold therefore triggers 52 px earlier than before.
• A skin that paints somewhere other than the sidebar column's own element will not be followed — the rail falls back to the theme tokens for that skin.
• Icon components are rendered directly and must only depend on { size, active }; anything else degrades to a neutral placeholder square.

Development

# link the working copy into a profile, then restart the app
plugin_manager install_bundle target=link:/absolute/path/to/two-pane-sidebar

link: installs a symlink, so after that every edit to client.js is picked up by a page reload — no build, no copy step. Locale metadata (locale/*.json meta) is read at boot and needs a restart.

Filter the browser console by [two-pane-sidebar]; every degraded path logs a warning there.

License

MIT