dsh-mermaid-image-preview

A DeepSeek Harness Plugin for Previewing Mermaid Diagram Images

Preview Mermaid syntax as images via local rendering in DSH when a chat message contains a Mermaid fenced code block (```mermaid or ```mmd).

Features and how it works

• Preview mermaid diagrams by rendering images directly!
• Local renderer first! If it fails, it can fall back to an external or self-hosted rendering engine by configuring a fallback server.
• Nothing gets replaced: the preview is added below the agent's reply, so the original messages are not covered up or changed.
• Settings in Plugin page: adjust the plugin's runtime settings in the Plugins panel - no restart needed.
• Light/dark themes follow the UI automatically.

Support diagram types

The plugin renders diagrams locally with a built-in renderer. It supports 13 diagram types out of the box.

Rendered locally: flowchart, sequenceDiagram, classDiagram, stateDiagram, erDiagram, pie, journey, gitGraph, requirementDiagram, timeline, quadrantChart, packet-beta, xychart-beta

Expand: gantt, mindmap, block-beta, sankey-beta, architecture-beta, zenuml, C4Context

[!NOTE] You can enable the fallback to render expanded types — see Configuration below.

Installation

Install from github

Install with DeepSeek Harness Desktop (the desktop profile)

In DeepSeek Harness (Desktop), go to the Plugins panel, click the + Add plugin button, paste one of the URLs below, then click the Install button.

### latest release version
https://github.com/baconbao/dsh-mermaid-image-preview
### specific version
https://github.com/baconbao/dsh-mermaid-image-preview#<VERSION_TAG|GIT_TAG>
### dev version
https://github.com/baconbao/dsh-mermaid-image-preview#dev

[!NOTE] Make sure Git is installed on your machine before installing.

Install with DeepSeek Harness WebUI (the web profile)

### latest release version
$ npx @deepseek-ai/dsh plugin --profile web add github:baconbao/dsh-mermaid-image-preview

### specific version
$ npx @deepseek-ai/dsh plugin --profile web add github:baconbao/dsh-mermaid-image-preview#<VERSION_TAG|GIT_TAG>

### dev version
$ npx @deepseek-ai/dsh plugin --profile web add github:baconbao/dsh-mermaid-image-preview#dev

Install from source code

$ git clone https://github.com/baconbao/dsh-mermaid-image-preview
$ cd dsh-mermaid-image-preview
$ pnpm install
$ dsh plugin --profile web add .

[!IMPORTANT] Restart DSH after installing.

Configuration

Change runtime settings on the plugin page

The Plugins panel lists this plugin under Installed; open its page and the configuration block carries the runtime settings - no restart needed. Values are stored in localStorage and applied immediately across all sessions.

Change render server via configuration file

Diagrams are rendered locally by default. To use your own render server or enable the external fallback, edit the profile's cordis.patch.yml (e.g. ~/.dsh/profiles/web/cordis.patch.yml for WebUI, or ~/.dsh/profiles/desktop/cordis.patch.yml for Desktop):

- id: ui-dsh-mermaid-image-preview
  config:
    enableLocalRender: true
    fallbackRenderUrl: https://mermaid.ink
    enableFallback: false

• enableLocalRender: render locally (default true). Set it to false to always use the fallback server (enableFallback is ignored).
• fallbackRenderUrl: fallback render server (default https://mermaid.ink).
• enableFallback: use the fallback server when local rendering fails (default false).
• Restart DSH after changing these settings.
• To host your own fallback render server, see https://github.com/jihchi/mermaid.ink for the details.

Uninstallation

Unstall with DeepSeek Harness Desktop (the desktop profile)

Open this plugin's page in the Plugins panel, then click Uninstall.

Unstall with DeepSeek Harness WebUI (the web profile)

$ dsh plugin --profile web remove @baconbao/dsh-mermaid-image-preview

[!NOTE] Since v0.2.0, the plugin/package ID has been @baconbao/dsh-mermaid-image-preview (it was dsh-mermaid-image-preview before).

Test

Ask the agent to produce:

```mermaid
graph TD
  A[Start] --> B{Success?}
  B -->|Yes| C[Done]
  B -->|No| D[Retry]
```

Compatibility

Author

baconbao, vibe coding with AI

License

MIT