Draw.io Diagram Skill

Generate draw.io diagrams as native .drawio files. Optionally export to PNG, SVG, or PDF with the diagram XML embedded so the exported file remains editable in draw.io.

This skill is based on the draw.io CLI workflow from jgraph/drawio-mcp/skill-cli and adapted for GRC professionals.

How to Create a Diagram

1. Generate draw.io XML in mxGraphModel format for the requested diagram.
2. Write the XML to a .drawio file in the current working directory using the Write tool.
3. Validate XML well-formedness before claiming the diagram is ready.
4. Post-process edge routing when npx @drawio/postprocess is already available. Skip silently if it is unavailable. Do not install it or ask the user about it.
5. If the user requested png, svg, or pdf, locate the draw.io CLI, export with embedded XML, then delete the source .drawio file after a successful export.
6. If the CLI is not found, keep the .drawio file and tell the user they can install the draw.io desktop app to enable export or open the .drawio file directly.
7. Open the result when the environment supports it. If open fails, print the absolute file path.

Choosing the Output Format

Check the user's request for a format preference.

• create a flowchart -> flowchart.drawio
• png flowchart for login -> login-flow.drawio.png
• svg: ER diagram -> er-diagram.drawio.svg
• pdf architecture overview -> architecture-overview.drawio.pdf

If no format is mentioned, write the .drawio file.

| Format | Embed XML | Notes | |--------|-----------|-------| | drawio | Native | Editable source file | | png | Yes, -e | Viewable everywhere, editable in draw.io | | svg | Yes, -e | Scalable, editable in draw.io | | pdf | Yes, -e | Printable, editable in draw.io | | jpg | No | Lossy and not editable |

Use double extensions for exported editable files: name.drawio.png, name.drawio.svg, name.drawio.pdf.

draw.io CLI Location

Try drawio on PATH first. Then use platform fallbacks:

• macOS: /Applications/draw.io.app/Contents/MacOS/draw.io
• Linux: drawio
• Windows: C:\Program Files\draw.io\draw.io.exe
• WSL2: /mnt/c/Program Files/draw.io/draw.io.exe

Detect WSL2 with:

bash
grep -qi microsoft /proc/version 2>/dev/null && echo WSL2

Export command:

bash
drawio -x -f <format> -e -b 10 -o <output> <input.drawio>

WSL2 example:

bash
"/mnt/c/Program Files/draw.io/draw.io.exe" -x -f png -e -b 10 -o diagram.drawio.png diagram.drawio

Open commands:

• macOS: open <file>
• Linux: xdg-open <file>
• WSL2: cmd.exe /c start "" "$(wslpath -w <file>)"
• Windows: start <file>

XML Format

A .drawio file is native mxGraphModel XML. Always generate XML directly. Mermaid and CSV formats require conversion and should not be saved as native .drawio files.

Every diagram must have this structure:

xml
<mxGraphModel adaptiveColors="auto">
  <root>
    <mxCell id="0"/>
    <mxCell id="1" parent="0"/>
  </root>
</mxGraphModel>

Cell id="0" is the root layer. Cell id="1" is the default parent layer. All diagram elements use parent="1" unless the diagram intentionally uses multiple layers.

XML Reference

For complete draw.io XML guidance, fetch and follow:

https://raw.githubusercontent.com/jgraph/drawio-mcp/main/shared/xml-reference.md

Use it for styles, edge routing, containers, layers, tags, metadata, dark mode colors, and XML well-formedness rules.

GRC Diagram Conventions

• Include control IDs, frameworks, owners, evidence repositories, systems of record, and review cadence when known.
• Use swimlanes for roles or departments: GRC, Security, Engineering, Legal, Procurement, Vendor, Auditor, Executive.
• Use containers for system boundaries, audit scope, trust zones, cloud accounts, environments, and in-scope/out-of-scope areas.
• Use dashed edges for evidence paths, dotted edges for optional or manual paths, and solid edges for process or system flows.
• Use red/orange accents for risks, findings, exceptions, overdue items, and failed controls.
• Use green/blue accents for implemented controls, automated checks, approvals, and trusted evidence.
• Include a legend when colors or edge styles have compliance meaning.

CRITICAL: XML Well-Formedness

• NEVER include ANY XML comments (<!-- -->) in the output.
• Escape special characters in attribute values: &, <, >, ".
• Always use unique id values for each mxCell.
• Always include root cells id="0" and id="1".
• Every edge must have a child geometry element: <mxGeometry relative="1" as="geometry"/>.
• Validate XML with a parser before finalizing.