Introduction

The right-side file preview in DeepSeek Harness supports Markdown documents, but Mermaid diagrams are usually shown only as source code, requiring window switching or reliance on external services. Markdown Studio takes over DSH’s native preview renderer and integrates Markdown, Mermaid diagrams, KaTeX formulas, and code highlighting in the same rendering pipeline. The rendering engine is bundled with the package and works offline.

What Is It

Markdown Studio is a client-side plugin for DeepSeek Harness, maintained by BioAIEvolu. As an extension slot for DSH’s native document preview, it includes complete rendering engines for Markdown, Mermaid, KaTeX, and code highlighting, enabling fully offline rendering of documents and diagrams.

Core Features

  • Dual rendering in chat + document preview: Mermaid blocks in chat messages and Markdown files opened in the right-side panel are rendered into SVG diagrams using the same pipeline.
  • Mermaid diagrams: Supports all Mermaid 11 diagram types, including flowcharts, sequence diagrams, Gantt charts, and pie charts; each diagram has a toolbar for graphics/source code/fullscreen/download SVG; light and dark themes trigger automatic re-rendering.
  • Automatic syntax repair: Automatically fixes syntax errors in labels such as W2[Codex / Claude Code (ACP)] containing English brackets.
  • KaTeX mathematical formulas: Supports inline $...$ and block-level $$...$$ rendering.
  • Full GFM support: Supports tables, task lists, footnotes, strikethrough, and heading anchors.
  • Code highlighting: Integrates highlight.js.
  • Local images: Supports relative path resolution.
  • Security and offline: DOMPurify sanitizes HTML and SVG, and script execution is disabled; the rendering engine is bundled in the package and fully offline-capable.

Installation and Enablement

Prerequisites: The DeepSeek Harness version must be 0.2.0-rc.2 or higher.

Installation command:

dsh plugin --profile desktop add github:BioAIEvolu/dsh-md-studio

After installation, restart DSH Desktop and open any .md file in the right-side panel to enable it.

Typical Usage

  1. Toggle between source code and rendered view: After opening a Markdown file, the Markdown Studio badge and a View Source button appear at the top of the document, allowing you to switch between source and rendered views.
  2. Operating Mermaid diagrams: Each Mermaid diagram includes a toolbar that supports switching between graphics/source code, fullscreen (supports mouse wheel zooming and drag panning), and downloading SVG.
  3. Disabling and restoring defaults: Disable the plugin in plugin management to restore the official DeepSeek Harness renderer.

Use Cases and Notes

Use cases: Developers who frequently need to view Mermaid architecture diagrams, sequence diagrams, and Gantt charts, or who need to render KaTeX mathematical formulas, GFM tables, and footnotes.

Limitations and notes:

  • Requires DSH version 0.2.0-rc.2 or later.
  • Document limit is 2 million characters; each diagram is limited to 50,000 characters / 2,000 lines / 2,000 edges.
  • Security mechanisms: Mermaid output is sanitized, interactive clicks and external image references are disabled; scripts are not executed.
  • The plugin runs with the current DSH process permissions; it is recommended to review the source code and license before installation.

Conclusion

Markdown Studio solves the pain point in DeepSeek Harness’s native preview where Mermaid diagrams and mathematical formulas cannot be rendered. By taking over the rendering pipeline as a plugin, it provides a WYSIWYG offline document experience. See the links below for the project address.

Project Homepage | DeepSeek Harness