dsh-plugin-mermaid-gb-svg

A DeepSeek Harness plugin that turns Mermaid flowcharts into GB/T 1526-1989 compliant SVG (the Chinese national standard, identical to ISO 5807:1985), and exposes it to the model as one tool.

Preview

GB/T 1526-1989 symbol chart	Generated flowchart

Both SVGs are produced by this tool — the source .mmd files are in examples/.

Install

# 1) install into a profile (web shown here)
dsh plugin --profile web add dsh-plugin-mermaid-gb-svg

# 2) make the loader load it — append to $DSH_HOME/profiles/web/cordis.patch.yml

- insert:
    - id: mermaid-gb-svg
      name: dsh-plugin-mermaid-gb-svg
      # config:
      #   fontSize: 14
      #   paper: none

For local development point at the source directory instead: dsh plugin --profile web add /path/to/dsh-plugin-mermaid-gb-svg.

Tool: mermaid_to_gb_svg

Parameter	Type	Description
out	string, required	Output path. Ending in .svg = file name (multi-diagram gets -1/-2), otherwise output dir/prefix
source	string	Mermaid source (mutually exclusive with path)
path	string	Input .mmd/.mermaid, or .md containing ```mermaid blocks (all blocks extracted; nearest heading above becomes the caption)
title	string	Figure caption
dir	td|lr|bt|rl	Force flow direction
paper	none|auto|a4|a4l|a3|a3l	Sheet size; none (default) emits one large SVG, others paginate when the drawing does not fit
font_size	integer	Body font size in px (14 ≈ 10.5pt)
font_tu	boolean	Use technical-drawing font (GB/T 14691 FangSong)
caption	boolean	Draw the caption (default true)

Returns files, diagrams, pages, summary, warnings.

GB/T 1526-1989 symbols

Symbol	Meaning	Mermaid syntax
rounded rectangle	terminal (start/end)	A([x]) A((x)) A(x)
rectangle	process	A[x]
diamond	decision	A{x}
parallelogram	data (input/output)	A[/x/] A[\x\]
hexagon	preparation	A{{x}}
double-sided rectangle	predefined process	A[[x]]
cylinder	direct access storage	A[(x)]
trapezoid	manual operation	A{/x/}
sloped-top quad	manual input	A{\x\}
square bracket	annotation	A>x]
circle	connector (on page)	A@{ shape: connector, label: "A" }
pentagon	off-page connector	A@{ shape: off-page, label: "B" }
—	document / multi-document	A@{ shape: doc, label: "report" } / docs
—	display / delay	A@{ shape: display, label: "display" } / delay
—	internal storage	A@{ shape: internal-storage, label: "storage" }

shape accepts both Mermaid v11 names and Chinese names (处理/起止/判断/数据/准备/预定义处理/ 直接存取存储/人工输入/人工操作/文档/多文档/显示/延迟/内部存储/注释/连接符/换页连接符).

Drawing conventions

• Flow runs left-to-right or top-to-bottom; flowlines are orthogonal with solid arrowheads.
• Decision branches: 是 leaves the bottom vertex downward, 否 leaves the right vertex (going right first, then turning).
• Every incoming flowline enters a symbol vertically at its top centre.
• At most 3 bends per flowline — routes are tried in order 0→1→2→3 bends and the first one that does not cross a symbol wins.
• Geometry is self-checked after generation (overlaps, flowlines through symbols) and reported in warnings.

Pagination (optional)

With paper: a4 (or a3/auto), a drawing that does not fit is split:

• cuts fall in the gaps between layers (and between columns of symbols), never through a symbol;
• each sheet is sized in real millimetres (width="210mm" height="297mm") with a frame, a binding margin and a (page n/N) caption;
• each broken flowline gets an off-page connector (pentagon) pointing along the flow, and the connector sits at the same place with the same label on both sheets.

Configuration

Key	Default	Meaning
font	SimSun, '宋体', 'Microsoft YaHei', sans-serif	Font family
fontSize	14	Body font size (px)
stroke	1.6	Line width
paper	none	Default sheet size

Sandbox

Writes go through the Harness ctx.fs seam with the session's sandbox policy, and support the same one-shot sandbox_permissions + justification escalation retry as the built-in write tool.

Development

npm test        # test/engine.test.mjs + test/plugin.test.mjs

lib/engine.js is generated from the CLI version (tools/mermaid2gb-svg.js) so both stay in sync; edit the CLI and regenerate rather than editing the engine directly.

Feedback

Feedback is what decides what gets built next — especially standard-compliance corrections, since GB/T 1526-1989 has details that are easy to get subtly wrong.

Channel	Use it for
Issues	Bugs, symbol corrections (there is a dedicated template — please cite the clause/figure), feature requests
Discussions	Usage questions, layout/typography opinions, open-ended ideas
sandyyst@hotmail.com	Anything you would rather not post publicly

When reporting a problem, attach the Mermaid source. A one-line description plus the .mmd is usually enough to reproduce it — the generated diagram, the tool's warnings array, and your plugin version help too.

If the tool reports geometry warnings, the output already carries the link to the issue tracker — that is the moment the report is most useful.

License

MIT