Introduction¶

To get an agent to “draw a flowchart” within DeepSeek Harness (DSH), there are two common approaches: one is to let the model output a snippet of Mermaid source code, which is then manually pasted into a renderer to generate the image; the other is to write a script tool that directly manipulates the file system, allowing the model to generate the file and write it to disk autonomously. The former breaks the workflow outside of the conversation, while the latter bypasses Harness’s file writing approval and sandbox policies.

deepseek-harness-flowchart takes a different path: it mounts a render_flowchart tool for DSH that renders the Mermaid flowchart locally into a themed, self-contained SVG, delegating file writing nestedly to Harness’s registered write tool. DSH’s philosophy is “everything is a plugin,” and this repository serves as a directly installable profile bundle.

About This¶

lizhecome/deepseek-harness-flowchart is a DeepSeek Harness plugin maintained by lizhecome. Its npm package name is @lizhecome/dsh-flowchart, version 0.1.0, and it is released under the MIT license. Upon installation, it adds the render_flowchart tool, rendering Mermaid flowchart source code into exquisite, themed, and self-contained SVGs. The community directory page categorizes it under the “Fun Outfit” category.

The rendering is completely local and deterministic, involving no LLM or network requests. It is built upon beautiful-mermaid 1.1.3 to handle Mermaid parsing, layout, theming, and SVG generation.

Core Features¶

render_flowchart Tool¶

The tool parameters are as follows:

There are 15 supported themes in total: 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, one-dark.

Input Restrictions¶

It only accepts Mermaid flowchart/graph documents with explicit directions (TD/TB/BT/LR/RL). Sequence diagrams, class diagrams, state diagrams, ER diagrams, XY diagrams, and other Mermaid chart types are rejected.

Rendering Security¶

Before distributing the SVG, the plugin performs a cleanup: it removes external font imports from the renderer, rejects scripts, event handlers, embedded browser documents, JavaScript URLs, and external hrefs, and applies a maxSvgBytes limit to the final self-contained result.

Reusing the write Tool¶

The plugin never writes files directly via Node’s environment file system. The generated SVG content is distributed via nested calls to Harness’s registered write tool. Consequently, tool limitations, approvals, sandbox policies, read-before-overwrite rules, cancellations, and final result normalization remain fully enforced. If the write tool is unavailable or rejected, render_flowchart will fail rather than claim success.

Installation and Enablement¶

Requires DeepSeek Harness 0.1.0-rc.6 or later, and the GitHub CLI must have access to the repository (the README marks it as private). The installation consists of three steps:

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

First clone the repository using the GitHub CLI, then add it to the web profile within the repository directory. The README explains that add . anchors to the checkout directory of the invocation before pnpm switches to the profile directory. The package manifest declares a dsh.bundle patch, which automatically mounts the tool and its invariant companion package during installation.

For one-off tasks, you can use the headless profile instead of web. The uninstall command is as follows:

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

Typical Usage¶

Describe the desired flowchart to the agent and specify the SVG output location, 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 will call render_flowchart, with the passed Mermaid source code looking like:

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

A successful call only returns the output path, theme, and byte count; the SVG body is passed through the nested write tool and will not be copied into the parent model’s result. The model only sees a tool schema; changes in configuration or tool availability are reflected in the request’s tool-schema prefix.

Configuration¶

Subsequent profile patches replace the config line-by-line, so you need to re-declare all fields you wish to preserve:

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

Invalid boundary values or the configuration of unavailable themes will cause the plugin to fail directly during loading.

Use Cases and Notes¶

Suitable for teams that frequently need to generate flowchart documentation in DSH: architecture descriptions, checkout processes, etc. They want the results to be directly themeable, self-contained SVGs ready for storage, without relaxing file writing policies.

Before use, there are a few points to confirm:

1. Only supports flowcharts; other Mermaid charts are rejected. Only outputs SVG, no PNG/PDF conversion.
2. Overwriting existing files follows the policy of the installed write tool; the agent may need to read the file first.
3. After removing web font imports, viewers will use the local Inter font or system sans-serif fonts.
4. The plugin runs with the permissions of the current dsh process. It is recommended to check the source code and license before installation (this project is MIT).
5. The README marks the repository as private; cloning requires the GitHub CLI to have corresponding access permissions.

Conclusion¶

The value of this plugin lies in integrating the step from “Mermaid source code” to “deliverable SVG file” into the agent’s toolchain: local, deterministic rendering with no network requests, file writing still goes through Harness’s existing write tool and its policies, and the 15 themes allow the output to be directly inserted into documentation.

• Directory page: https://www.skillhub.cn/plugins/lizhecome/deepseek-harness-flowchart
• GitHub: https://github.com/lizhecome/deepseek-harness-flowchart