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.

Install

From npm after publication:

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

From this checkout during development:

dsh plugin --profile web add /home/syncended/deepseek-harness-split-screen

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

dsh plugin --profile web add -w /home/syncended/deepseek-harness-split-screen

Restart dsh web after first installation and refresh the existing Web GUI. A Split action appears in the native sidebar footer.

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 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.

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 conversation occupant for the center workspace; 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, history, streaming, prompts, permissions, token/context metrics, cancellation, and paging.
• 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 optional session ids. Removing a leaf collapses its parent, while header drag-and-drop swaps leaf session assignments 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.

Requirements

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

License

MIT — see LICENSE.