dsh-better-markdown

dsh-better-markdown is a DeepSeek Harness Web client plugin. Once installed, every assistant Markdown block carrying streaming state is parsed and rendered by markstream-react. The same renderer stays mounted after the stream settles, so completion does not swap the message back to a different Markdown implementation.

markstream-react is the official React package from the Simon-He95/markstream-vue monorepo. This plugin does not add the Vue runtime to Harness.

Why Markstream React

• Streaming-first parsing: keeps handling incomplete emphasis, code fences, lists, tables, and math while LLM tokens are still arriving.
• No completion-time renderer swap: streaming and settled assistant messages share the same Markstream renderer.
• Richer output: common Markdown, tables, task lists, blockquotes, links, images, KaTeX math, and Mermaid diagrams.
• Harness scroll-container compatibility: disables viewport lazy mounting that cannot reliably observe nodes inside the chat scroller, preventing visible content from getting stuck as skeleton placeholders.
• Full Markstream code blocks: fenced code is rendered by Markstream's MarkdownCodeBlockNode and stream-markdown, with streaming Shiki highlighting plus language headers, copy actions, and expansion. Reasoning, attachments, and interruption states retain Harness behavior.
• Explicit security policy: raw HTML uses htmlPolicy="escape"; links, images, and settled file mentions retain Harness restrictions; Mermaid runs in strict mode.

Screenshots

Markstream code blocks

Images, links, and KaTeX math

Mermaid diagrams

Feature scope

How it works

The plugin uses the public Harness client-module and slot-shadowing APIs. It does not patch Harness files or replace React globally.

Assistant token stream
  -> Harness session projection
  -> conversation.chat.node / assistant-step
       |- priority -100: BetterAssistantNodeView
       |                  -> markstream-react  (active)
       |                       `- fenced code -> stream-markdown -> Shiki
       `- priority    0: Harness built-in      (fallback)

The shadow entry handles normal rendering. If the plugin renderer throws or is unloaded, the original Harness renderer remains registered and takes over.

Installation

Install from npm (recommended)

Prerequisite: a working DeepSeek Harness Web installation.

dsh plugin --profile web add dsh-better-markdown
dsh --profile web --dump-config
dsh --profile web

Update the plugin:

dsh plugin --profile web add dsh-better-markdown@latest

Install from source

Prerequisites: a working DeepSeek Harness Web installation, Node.js 20+, and pnpm 10+.

git clone https://github.com/zerob13/dsh-better-markdown.git
cd dsh-better-markdown
pnpm install
pnpm run check
pnpm run build
dsh plugin --profile web add "$(pwd)"
dsh --profile web --dump-config
dsh --profile web

On Windows PowerShell, replace "$(pwd)" with (Get-Location).Path.

The composed configuration should include:

# == dsh-better-markdown
- id: better-markdown
  name: dsh-better-markdown

Rendered assistant Markdown carries this verification marker:

<div data-markdown-renderer="markstream-react">

Install directly from Git

Git dependencies run the repository's prepare build. pnpm 10/11 may require explicit permission in the Web profile's pnpm-workspace.yaml:

allowBuilds:
  dsh-better-markdown: true

Then install and start Harness:

dsh plugin --profile web add git+https://github.com/zerob13/dsh-better-markdown.git
dsh --profile web

Pin a commit SHA for production use instead of following the default branch indefinitely.

Remove

To remove the plugin:

dsh plugin --profile web remove dsh-better-markdown

Unloading disposes the slot shadow and Markstream component policy, immediately restoring the built-in renderer.

Bundle trade-offs

• markstream-react: 0.0.55
• mermaid: 11.16.1
• stream-markdown: 0.0.16
• shiki: 4.4.3
• Current browser bundle: about 7.40 MB, about 1.59 MB gzip
• Mermaid and Shiki syntax highlighting are bundled for offline use; Shiki uses its JavaScript regex engine and a fine-grained bundle of 34 common languages
• The optional Monaco runtime, D2, and Infographic peers are not bundled; unknown code languages use Markstream's plain-text fallback

Removing Mermaid can substantially reduce the bundle, but Mermaid fences will no longer produce diagram previews.

Development

pnpm install
pnpm run check
pnpm run build
pnpm pack --dry-run

Maintainers release by matching the package.json version to a vX.Y.Z tag and publishing the corresponding GitHub Release. publish.yml validates the version, runs checks and a build, then publishes the public package through npm trusted publishing. Prereleases are not published.

Key files:

• src/client/index.ts: Markstream component policy and assistant slot shadow
• src/client/renderer.tsx: assistant node and Markdown renderer
• src/client/shiki.ts: fine-grained Shiki bundle for the single-file plugin build
• src/client/styles.css: Harness token adaptation
• cordis.patch.yml: plugin bundle row
• tests/plugin.spec.tsx: streaming, fallback, security, and Mermaid routing tests

Compatibility

• DeepSeek Harness 0.1.0-rc.5 or newer
• React 18 or newer
• Replaces only the Web conversation assistant-step
• Older Harness builds without priority-based slot shadowing fail at load time instead of mounting two renderers

Credits

• DeepSeek Harness
• markstream-vue / markstream-react
• Mermaid

License

MIT