Preface

The core philosophy of DeepSeek Harness (DSH) is “everything is a plugin.” In Web mode, multiple sessions often require switching between tabs to view, and frequent jumps can interrupt the workflow. This plugin aims to solve this problem. It aggregates multiple DSH sessions on a single screen and provides terminal-like session multiplexing.

Plugin Scope

syncended/deepseek-harness-split-screen is an iTerm-style session multiplexer for the DeepSeek Harness Web GUI. The plugin is maintained by syncended and follows the MIT license. It allows you to open multiple workspaces in a single window, with each pane able to point to different sessions or session stacks.

Core Features

The plugin supports the following operations and capabilities:

  • Multi-pane layout: Supports nested vertical and horizontal splits, up to 12 panes.
  • Interactive controls: Drag splitters to resize panes; drag pane title bars to swap sessions.
  • Session management: Each pane has independent local chat tabs. Selecting a session from the sidebar automatically adds it to the currently focused pane.
  • Real-time status: All panes display live streaming transcript text, session status, queued replies, and history loading.
  • Model control: Provides compact model and access mode selectors, including a protected “Full Access” option, as well as a clickable context ring with token metrics.
  • Persistence: Layout, split ratios, pane order, and unsent drafts are saved in the browser’s localStorage.
  • Language support: Supports multilingual UI.

Installation and Enablement

The installation process requires a DeepSeek Harness Web Profile.

  1. Run the installation command:
    dsh plugin --profile web add @syncended/dsh-split-screen
  1. After installation is complete, restart dsh web and refresh the Web GUI.
  2. At the bottom of the native sidebar, a Split button will appear. Click it to enter Split workspace mode.

Typical Usage

After entering Split mode, you can perform the following operations:

  1. Enable Split mode: Click the Split button at the bottom of the sidebar.
  2. Split panes: Select a pane and choose Split vertically or Split horizontally from its title bar.
  3. Add sessions: Select a session in the sidebar. If the current pane does not have a tab for that session, it will be added as a new tab; if it already exists, that tab will be focused.
  4. Quick add: Use the + button on the pane title bar to add a tab for that pane without changing the sidebar selection.
  5. Adjust layout: Drag splitters to resize panes, or drag one pane’s title onto another pane to swap the session stacks of the two panes.
  6. Restore native view: Click Back to Chat, or click the Split button at the bottom of the sidebar again, to restore the native DeepSeek Harness chat interface.

Keyboard Shortcuts

  • Alt+Shift+V: Split the current pane vertically
  • Alt+Shift+H: Split the current pane horizontally
  • Enter: Send in the focused input field
  • Shift+Enter: Insert a newline in the focused input field

Notes and Limitations

This plugin manages layout through browser local storage. Special attention should be paid to the following scenarios and limitations:

  • Displayed content: Compact panes render only chat text and tool/command lines, and do not display the full card registry.
  • Advanced workflows: Features such as structured approval, plan review, and ask_user_question must be completed in the main view (native Chat). The plugin provides direct navigation to that view.
  • Skills and commands: Skill insertion, slash commands, and the rich + menu remain in native Chat to keep panes compact.
  • File upload: The current version sends only text prompts; attachments are displayed only in history.
  • Session sources: The plugin can only aggregate sessions exposed by the same dsh web Host and Profile. It does not support aggregating sessions across servers or remote URLs.
  • Data scope: Browser persistence is limited to the current origin and Profile. Click Reset layout to clear saved arrangements; clearing site storage also removes the layout and drafts.

Summary

The DeepSeek Harness Split Screen plugin provides a lightweight solution for parallel handling of multiple sessions. It does not change DeepSeek Harness’s core architecture; instead, it mounts to the Web GUI and delivers a terminal-like split-view session experience without leaving the browser tab. For developers who need to monitor multiple sessions simultaneously or compare outputs from different models, this tool can effectively improve operational efficiency.