draw.io Diagrammer

Generate aesthetically beautiful, professional draw.io diagrams (flowcharts, ERD, architecture, sequence, class) with a mandatory visual QA loop — so your agent doesn't just build diagrams, it builds diagrams that look right. Use when user requests any diagram, flowchart, or system visualization.

draw.io Diagrammer Skill

When to use this skill

• User requests a flowchart, process map, or workflow diagram
• User requests an ERD, database diagram, or entity relationship model
• User requests an architecture, system, or component diagram
• User requests a class, sequence, or UML diagram
• User says "draw.io", "diagram", "flowchart", "visualize this process"
• User asks to update, fix, or extend an existing .drawio file

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MANDATORY — Read before generating anything

1. Detect diagram type first — see diagram-types/ references before writing XML
2. Apply universal box style standards — see references/box-style-standards.md
3. All positions are hardcoded — no auto-layout exists in draw.io XML
4. Run the visual review loop after every export — see references/visual-review-protocol.md
5. Never declare done without a visual pass — export PNG, read it, fix it, repeat

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Diagram type detection

User says...	Reference file
"flowchart", "process", "steps", "workflow", "SOP"	references/diagram-types/flowchart.md
"ERD", "database", "tables", "entities", "foreign key"	references/diagram-types/erd.md
"architecture", "system", "components", "services"	references/diagram-types/layout.md
"class", "UML", "inheritance", "methods", "attributes"	references/diagram-types/class.md
"sequence", "interaction", "lifeline", "actor calls"	references/diagram-types/sequence.md

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Standard generation workflow

Step 1 — Load type reference

Read the correct references/diagram-types/ file before writing any XML.

Step 2 — Plan all elements

List every node, connection, and section before coding. Do not improvise layout mid-build.

Step 3 — Apply universal box style

Every node must include the universal spacing attributes from references/box-style-standards.md.

Step 4 — Create output folder and write XML

bash

mkdir -p ./diagrams

Save to:

text

./diagrams/<diagram-name>.drawio

Pre-save checklist:

• All mxCell elements have unique sequential numeric IDs
• Universal box spacing applied to every node style: spacingLeft=12;spacingRight=12;spacingTop=10;spacingBottom=10;verticalAlign=top;
• Arrows use chained routing, not fan-out from single source to many targets
• Minimum 15–20px gap between any two boxes (verify sub-item list bottom vs next section top)
• Heights calculated with the formula in box-style-standards.md (×16px per line at fontSize=10)
• Wide-text panels (notes, descriptions) are 530px+ wide — not 460px or less
• No literal \n in value attributes — use 
 for line breaks
• verticalAlign=top on all multi-line content boxes

Step 5 — Export PNG and run visual review loop

bash

/Applications/draw.io.app/Contents/MacOS/draw.io --export --format png --output ./diagrams/<name>.png --scale 2 --border 30 ./diagrams/<name>.drawio

Then follow the full protocol in references/visual-review-protocol.md.

Step 6 — Deliver

Send the PNG to the user first. For larger diagrams, send section screenshots (top, middle, bottom) before the full image.

Then ask which additional formats they want:

text

The diagram is ready. Which format would you like?

1 — PNG image (ready to view)
2 — .drawio file (editable in draw.io)
3 — SVG (scalable vector)
4 — PDF
5 — All of the above

Reply with the number(s) of your choice.

For Drive delivery or custom output paths, follow references/workflow-sop.md.

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CLI reference

bash

# macOS — Export PNG (standard)
/Applications/draw.io.app/Contents/MacOS/draw.io --export --format png --output <out.png> --scale 2 --border 30 <file.drawio>

# macOS — Export high-res PNG
/Applications/draw.io.app/Contents/MacOS/draw.io --export --format png --output <out.png> --scale 3 --border 30 <file.drawio>

# macOS — Export SVG
/Applications/draw.io.app/Contents/MacOS/draw.io --export --format svg --output <out.svg> <file.drawio>

# macOS — Export PDF
/Applications/draw.io.app/Contents/MacOS/draw.io --export --format pdf --output <out.pdf> <file.drawio>

# Linux / headless — Export PNG
xvfb-run -a drawio --export --format png --output <out.png> --scale 2 --border 30 <file.drawio>

# Linux / headless — Export SVG
xvfb-run -a drawio --export --format svg --output <out.svg> <file.drawio>