dsh-plugin-mermaid-preview

Opening a .mmd or .mermaid file in DeepSeek Harness usually gives you a wall of graph TD text—syntactically valid, but hard to absorb at a glance. dsh-plugin-mermaid-preview renders those files directly as SVG diagrams in the right-panel document viewer, so flowcharts, sequence charts, and state diagrams become visual rather than something you reconstruct in your head.

Inline mermaid code blocks are handled conservatively: they stay as code blocks and the plugin logs a single informational line, ensuring the surrounding file preview is never disrupted. Zooming is applied through the SVG width and height attributes instead of CSS transforms, and every step is snapped to the device-pixel grid to prevent the half-pixel blur that appears on high-DPI displays or at 125 percent scaling. The full mermaid runtime, including every grammar parser, is inlined into a single ~7 MB script—fetched once and cached by revision—with no reliance on dynamic imports.

Built for engineers and document maintainers who author or review architecture docs, API sequence diagrams, and state-machine charts inside Harness: open the file and the diagram is there, no need to switch to an external Mermaid tool.