DeepSeek Harness Flowchart

An installable DeepSeek Harness profile bundle that adds a render_flowchart tool. The tool turns Mermaid flowchart source into a polished, themed, self-contained SVG and delegates file creation to Harness's existing write tool.

中文说明

Install

Requires DeepSeek Harness 0.1.0-rc.6 or later and GitHub CLI access to this private repository.

gh repo clone lizhecome/deepseek-harness-flowchart
cd deepseek-harness-flowchart
dsh plugin --profile web add --ignore-workspace-root-check .

Use headless instead of web for one-shot tasks. DeepSeek Harness anchors add . to the invoking checkout before pnpm switches to the profile directory. The package manifest declares a dsh.bundle patch, so installation mounts the tool and its invariant companion automatically.

To remove it:

dsh plugin --profile web remove --ignore-workspace-root-check @lizhecome/dsh-flowchart

Use

Ask the agent for a flowchart and name the SVG destination, for example:

Create a left-to-right flowchart of the checkout process and save it as docs/checkout.svg. Use the catppuccin-mocha theme.

The model calls render_flowchart with Mermaid source similar to:

flowchart LR
  cart([Cart]) --> payment{Payment valid?}
  payment -->|Yes| success([Order placed])
  payment -->|No| retry[Retry payment]
  retry --> payment

The tool accepts only Mermaid flowchart/graph documents with an explicit TD, TB, BT, LR, or RL direction. The destination must end in .svg.

Tool arguments

Argument	Required	Meaning
source	yes	Complete Mermaid flowchart source.
file_path	yes	SVG destination resolved by the installed write tool.
theme	no	One of the 15 themes below; defaults to the deployment setting.
transparent	no	Remove the theme background; default false.
padding	no	Canvas padding, 0–200; default 40.
node_spacing	no	Horizontal sibling spacing, 8–160; default 24.
layer_spacing	no	Vertical layer spacing, 8–240; default 40.

Themes: zinc-light, zinc-dark, tokyo-night, tokyo-night-storm, tokyo-night-light, catppuccin-mocha, catppuccin-latte, nord, nord-light, dracula, github-light, github-dark, solarized-light, solarized-dark, and one-dark.

Configuration

Later profile patches replace a row's complete config, so restate every field you want to keep:

- id: flowchart
  config:
    defaultTheme: github-light
    maxSourceChars: 50000
    maxSvgBytes: 2000000

Field	Default	Meaning
defaultTheme	tokyo-night	Theme used when a tool call omits theme.
maxSourceChars	50000	Positive integer limit on complete Mermaid input.
maxSvgBytes	2000000	Positive integer limit on the complete UTF-8 SVG.

Invalid bounds or an unavailable configured theme fail at plugin load.

Filesystem and SVG safety

The plugin never writes through Node's ambient filesystem. It dispatches the generated content to the registered Harness write tool as a nested call, so tool restrictions, approval, sandbox policy, read-before-overwrite rules, cancellation, and final result normalization remain authoritative. If write is unavailable or denied, render_flowchart fails without claiming success.

Before dispatching the SVG, the plugin removes renderer-owned external font imports, rejects scripts, event handlers, embedded browser documents, JavaScript URLs, and external href values, and applies maxSvgBytes to the complete self-contained result.

Model and token effects

The model sees one tool schema. A successful call returns only the output path, theme, and byte count; the SVG body is passed to the nested write tool but is not copied into the parent model result. Changing package configuration or tool availability changes the request's tool-schema prefix.

Rendering is local and deterministic; it makes no LLM or network request. The implementation uses beautiful-mermaid 1.1.3 for Mermaid parsing, layout, theming, and SVG generation.

Known limitations

• Only flowcharts are accepted; sequence, class, state, ER, XY, and other Mermaid diagrams are rejected.
• Output is SVG only. PNG/PDF conversion is not included.
• Existing-file replacement follows the installed write tool policy and may require the agent to read the file first.
• The removed web-font import means viewers use their local Inter or system sans-serif font.

Development

pnpm install
pnpm run check

Tests boot the published Harness tool runtime, filesystem provider, and real write tool. They verify themed SVG creation, concise result/file agreement, limits, unsupported input, missing-write failure, presentation metadata, and registration disposal.