Mermaid Render

Gives the agent a render_mermaid tool that turns Mermaid source into an SVG or PNG file. Rendering uses a Chromium-family browser and mermaid.js (same family of library the web UI uses).

Configuration

plugins:
  - module: codumentor.plugins.mermaid_render
    class: MermaidRenderPlugin
    args:
      enabled: true
      target_agents: "main"
      timeout: 30
      # mermaid_js_url: "file:///opt/mermaid/mermaid.min.js"  # offline

• enabled (optional, default true).
• target_agents (optional, default "main"): "main", "subagent", or "all".
• timeout (optional, default 30): Per-render timeout in seconds (minimum 1).
• mermaid_js_url (optional): Where the browser loads mermaid.js (default: jsDelivr mermaid@11). Use a file:// path or a self-hosted copy on air-gapped hosts.
• default_theme (optional): "default", "dark", "forest", "neutral", or "base" (default "default").
• default_background (optional): CSS colour; "transparent" is meaningful for PNG (default "white").

Users can enable or disable the plugin for themselves in settings.

Tool: render_mermaid

Argument	Required	Description
source	yes	Mermaid diagram source.
output_path	yes	Where to write the image. Relative paths use the working directory; parent dirs are created.
format	no	svg or png. Defaults from the path extension, otherwise svg.
theme	no	Overrides default_theme.
background	no	Overrides default_background.

Returns the absolute path plus format, size, and theme.

Notes

• Browser: Chrome, Edge, or Chromium must be installed on the host. If none is found, the first call returns install instructions. A previously installed Playwright Chromium (~/.cache/ms-playwright) is reused if present; otherwise a normal system browser is enough. Non-standard location: set CODUMENTOR_CHROME_PATH to the binary.
• Diagrams are rendered with Mermaid securityLevel: 'strict'.
• background: "transparent" with PNG produces an alpha channel.