DeepSeek Harness — Session Split Screen

An iTerm-style session multiplexer for the DeepSeek Harness Web GUI. It puts several Harness sessions on one screen and lets each pane point at a different workspace.

Features

• Nested vertical (side-by-side) and horizontal (stacked) splits.
• Drag any divider to resize adjacent panes.
• Drag one pane header onto another to swap their sessions.
• Up to 12 panes in one layout.
• Dedicated Split workspace mode in the main conversation area, toggled from the native sidebar footer.
• Pane-local chat tabs: focus a pane, then choose a session from the standard Harness session list or the pane’s + menu.
• Sidebar selection adds or activates a tab in the focused pane without changing another session’s native Chat view.
• Live streaming transcript, session status, queued replies, stop action, and older-history loading in every pane.
• Compact per-pane model and access-mode popup selectors with icons, including guarded Full access selection.
• Clickable context ring with used/remaining/limit details, plus live turn/step counts, token throughput (tok/s), input/output token totals, and cache-hit metrics.
• Structured-input indicator for approvals, plan review, and questions, with a jump to the full Harness view.
• Layout, split ratios, pane order, selected session ids, and unsent pane drafts persist in browser localStorage.
• English, Russian, and Chinese UI tied to the Harness locale, dark-theme token compatibility, and keyboard controls.

Requirements

• DeepSeek Harness 0.1.0-rc.6 or compatible.
• The Web profile (dsh web).
• Node.js 18 or newer.

Install

Install from npm:

dsh plugin --profile web add @syncended/dsh-split-screen

From this checkout during development:

dsh plugin --profile web add /absolute/path/to/deepseek-harness-split-screen

Some pnpm-backed profiles require the workspace-root flag:

dsh plugin --profile web add -w /absolute/path/to/deepseek-harness-split-screen

The package declares a DSH bundle; no manual plugin entry is required. Restart dsh web after installing or upgrading and refresh the existing Web GUI. A Split action appears in the native sidebar footer.

No environment variables, remote URL, or separate connection are required. Panes can use only sessions exposed by the same dsh web Host and profile.

To remove the plugin:

dsh plugin --profile web remove @syncended/dsh-split-screen

Restart the Host after removal.

Usage

1. Click Split in the native sidebar footer. The workspace temporarily occupies the center conversation column.
2. Select a pane and use Split vertically or Split horizontally in its header.
3. With the target pane focused, choose a session in the native sidebar. It is added as a tab in that pane; selecting an already-open session focuses its existing tab.
4. Use the pane’s + button to add tabs without changing the sidebar selection. Closing a pane tab never deletes its Harness session.
5. Resize with the divider or drag one pane header onto another to swap complete pane tab stacks.
6. Click Back to Chat or the sidebar Split action again. Harness restores its native conversation surface on the active pane’s session.

Keyboard shortcuts

| Shortcut | Action | | --- | --- | | Alt+Shift+V | Split the active pane vertically | | Alt+Shift+H | Split the active pane horizontally | | Enter | Send from the focused composer | | Shift+Enter | Insert a newline |

Workspace and persistence behavior

A single dsh web Host exposes all workspaces registered in that profile. The plugin can mix their sessions freely in one layout; panes do not have to share a cwd or repository.

This version does not aggregate sessions from separate DSH server processes or different remote URLs. Those are separate Hosts and would require a multi-connection runtime rather than a client layout plugin.

Layout and drafts are scoped to the current browser origin and profile. Use Reset layout to clear the saved arrangement. Clearing the site's browser storage also removes the layout and unsent pane drafts.

Development

npm run check
npm test
npm pack --dry-run

The package has two runtime faces:

• lib/index.js — no-op Host loader entry.
• lib/client.js — dependency-free DSH lazy client module.

The browser half uses supported public seams:

• A dynamically registered main.conversation occupant for the center workspace (conversation on older Hosts); disposing it restores Harness’s shipped ConversationRoot unchanged.
• sidebar.footer.action for the persistent Split mode toggle.
• ctx.sessions.list, open(id), binding(id).session, and public session projections for native selection tracking, prompts, permissions, token/context metrics, cancellation, and paging.
• ctx.uiConversation.binding(id).target("chat") for history and streaming on current Hosts, with legacy session-snapshot fallback on older versions.
• ctx.modelDirectories.directoryFor(id) for the shared per-session model catalog and selection state.
• ctx.workspaces.list for native workspace and session labeling.

The layout is a persisted binary tree. Split nodes own direction and ratio; leaf nodes own stable pane IDs and pane-local tab stacks. Removing a leaf collapses its parent, while header drag-and-drop swaps complete pane tab stacks without rebuilding the tree.

Current limitations

• The compact panes intentionally render conversational text and compact tool/command rows, not the full Harness card registry.
• Structured approvals, plan review, and ask_user_question must be completed in the normal main view; the pane provides a direct jump there.
• Skills, slash-command insertion, and the rich + menu intentionally stay in native Chat to keep small panes compact.
• Attachments can be represented in history, but this version sends text prompts only.
• Browser persistence is local to the current origin/profile.

License

MIT — see LICENSE.