When developing agents or operating workflows in DeepSeek Harness, it is often necessary to perform parallel follow-up questions or independent thinking alongside the main conversation. The dsh-side-chat plugin addresses this need by opening a native, independent, and hidden child session beside the main session. It does not occupy sub-agent routing, does not pollute the conversation list, and supports understanding the main conversation context on demand.

This is a DeepSeek Harness workflow plugin maintained by KarlOfLaw, version 1.2.1, licensed under the MIT License. It reuses native DSH session components and creates a truly parallel session through the parentSession relationship.

Core Features

  • Genuinely independent session: Has its own transcript and a shared workspace.
  • Complete native UI: Directly reuses the native DSH session interface, supporting model selection, attachments, tools, and approval flows.
  • Fully usable before sending: Even an empty side chat displays the native session body, input box, and hide/close controls.
  • On-demand main conversation understanding: Does not copy the main conversation record; reads relevant parent-session fragments on demand via side_chat_context.
  • True side-by-side layout: Supports dragging the center divider to adjust proportions; the side chat ratio is limited to 25%–70%.
  • No conversation list pollution: New side chats are archived immediately and do not appear in the workspace left-side list.
  • Select text and ask: Select the text of a main message and click “Quote to Side Chat”; the quoted reference can be previewed and deleted, and is added to the context only when sending.
  • Compatibility and control: Compatible with Better Sidebar, and supports hiding, restoring, and deleting.

Installation and Enabling

DeepSeek Harness 0.1 or 0.2 and Node.js 22+ must be installed.

After downloading dsh-side-chat-1.2.1.tgz, run the installation command:

dsh plugin --profile web add .\dsh-side-chat-1.2.1.tgz

Start DSH from the project directory:

dsh web --port 3080

Typical Usage

  1. Open the main conversation and click the “+” icon on the message bubble in the header; the side chat will appear immediately.
  2. Use tools and approval flows in the side chat, operating it like a regular DSH session.
  3. Drag the center divider to adjust the proportion; after focusing the divider, you can fine-tune it with arrow keys.
  4. Select the text of a main message and click “Quote to Side Chat”; a quote hint will appear above the input box and can be deleted.
  5. Click the panel icon in the side chat header to hide it; the close button allows choosing “Retain Conversation” or “Delete and Close.”

Applicable Scenarios and Notes

It is suitable for scenarios that require in-depth follow-up, code review, or parallel debugging alongside the main conversation.

Notes:
* A single selected-text quote retains at most 8,000 characters.
* Mobile long-press text selection and the touch action bar are not yet specifically optimized.
* The plugin depends on the public SessionProvider and conversation.content Factory, and secure deletion supports DSH 0.1/0.2 JSONL and Zstandard JSONL session files.

With this plugin, you can conduct parallel conversations using DSH’s native capabilities without leaving the main interface, keeping the main session clean while providing independent space for thinking. For more details and source code, refer to the GitHub repository.