Draw.io Diagrams

Overview

Generate

.drawio

Supported formats: PNG, SVG, PDF, JPG — no browser automation needed.

PNG, SVG, and PDF exports support

--embed-diagram

-e

name.drawio.png

When to Use

Explicit triggers: user says "diagram", "visualize", "flowchart", "draw", "architecture diagram", "process flow", "ER diagram", "UML", "sequence diagram", "class diagram", "neural network", "model architecture"

Proactive triggers:

• Explaining a system with 3+ interacting components
• Describing a multi-step process or decision tree
• Comparing architectures or approaches side by side

Skip when: a simple list or table suffices, or user is in a quick Q&A flow

Prerequisites

The draw.io desktop app must be installed and the CLI accessible:

# macOS (Homebrew — recommended)
brew install --cask drawio
draw.io --version

# macOS (full path if not in PATH)
/Applications/draw.io.app/Contents/MacOS/draw.io --version

# Windows
"C:\Program Files\draw.io\draw.io.exe" --version

# Linux
draw.io --version

Install draw.io desktop if missing:

• macOS:

  brew install --cask drawio

  or download from https://github.com/jgraph/drawio-desktop/releases
• Windows: download installer from https://github.com/jgraph/drawio-desktop/releases
• Linux: download

  .deb

  /

  .rpm

  from https://github.com/jgraph/drawio-desktop/releases

Workflow

Before starting the workflow, assess whether the user's request is specific enough. If key details are missing, ask 1-3 focused questions:

• Diagram type — which preset? (ERD, UML, Sequence, Architecture, ML/DL, Flowchart, or general)
• Output format — PNG (default), SVG, PDF, or JPG?
• Scope/fidelity — how many components? Any specific technologies or labels?

Skip clarification if the request already specifies these details or is clearly simple (e.g., "draw a flowchart of X").

0. Check for updates (first use per conversation) — run

   bash <this-skill-dir>/update.sh

   once before the first diagram. The script self-throttles to once per 12 hours and is silent when up to date, offline, or not a git install. If it prints an update notice, include that notice verbatim in your reply to the user, then continue normally — do not block or delay on it.
1. Check deps — verify

   draw.io --version

   succeeds; note platform for correct CLI path
2. Plan — identify shapes, relationships, layout (LR or TB), group by tier/layer
3. Generate — write

   .drawio

   XML file to disk (output dir same as user's working dir)
4. Export draft — run CLI to produce PNG for preview
5. Self-check — use the agent's built-in vision capability to read the exported PNG, catch obvious issues, auto-fix before showing user (requires a vision-enabled model such as Claude Sonnet/Opus)
6. Review loop — show image to user, collect feedback, apply targeted XML edits, re-export, repeat until approved
7. Final export — export approved version to all requested formats, report file paths

Step 5: Self-Check

After exporting the draft PNG, use the agent's vision capability (e.g., Claude's image input) to read the image and check for these issues before showing the user. If the agent does not support vision, skip self-check and show the PNG directly:

source

target

<Array as="points">

• Max 2 self-check rounds — if issues remain after 2 fixes, show the user anyway
• Re-export after each fix and re-read the new PNG

Step 6: Review Loop

After self-check, show the exported image and ask the user for feedback.

Targeted edit rules — for each type of feedback, apply the minimal XML change:

mxCell

value

fillColor

strokeColor

style

mxCell

id

mxCell

source

target

x

y

mxGeometry

mxCell

width

height

mxGeometry

mxCell

mxCell

source

target

value

mxCell

Rules:

• For single-element changes: edit existing XML in place — preserves layout tuning from prior iterations
• For layout-wide changes (e.g., swap LR↔TB, "start over"): regenerate full XML
• Overwrite the same

  {name}.png

  each iteration — do not create

  v1

  ,

  v2

  ,

  v3

  files
• After applying edits, re-export and show the updated image
• Loop continues until user says approved / done / LGTM
• Safety valve: after 5 iteration rounds, suggest the user open the

  .drawio

  file in draw.io desktop for fine-grained adjustments

Step 7: Final Export

Once the user approves:

• Export to all requested formats (PNG, SVG, PDF, JPG) — default to PNG if not specified
• Report file paths for both the

  .drawio

  source file and exported image(s)
• Auto-launch: offer to open the

  .drawio

  file in draw.io desktop for fine-tuning —

  open diagram.drawio

  (macOS),

  xdg-open

  (Linux),

  start

  (Windows)
• Confirm files are saved and ready to use

Draw.io XML Structure

File skeleton

<?xml version="1.0" encoding="UTF-8"?>
<mxfile host="drawio" version="26.0.0">
  <diagram name="Page-1">
    <mxGraphModel>
      <root>
        <mxCell id="0" />
        <mxCell id="1" parent="0" />
        <!-- user shapes start at id="2" -->
      </root>
    </mxGraphModel>
  </diagram>
</mxfile>

Rules:

• id="0"

  and

  id="1"

  are required root cells — never omit them
• User shapes start at

  id="2"

  and increment sequentially
• All shapes have

  parent="1"

  (unless inside a container — then use container's id)
• All text uses

  html=1

  in style for proper rendering
• Never use

  --

  inside XML comments — it's illegal per XML spec and causes parse errors
• Escape special characters in attribute values:

  &

  ,

  <

  ,

  >

  ,

  "

• Multi-line text in labels: use

  


  for line breaks inside

  value

  attributes (not literal

  \n

  ). Example:

  value="Line 1
Line 2"

Shape types (vertex)

rounded=0

rounded=1

ellipse;

rhombus;

shape=mxgraph.aws4.resourceIcon;

shape=cylinder3;

swimlane;

Required properties

<!-- Rectangle / rounded box -->
<mxCell id="2" value="Label" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;" vertex="1" parent="1">
  <mxGeometry x="100" y="100" width="160" height="60" as="geometry" />
</mxCell>

<!-- Cylinder (database) -->
<mxCell id="3" value="DB" style="shape=cylinder3;whiteSpace=wrap;html=1;fillColor=#f5f5f5;strokeColor=#666666;fontColor=#333333;" vertex="1" parent="1">
  <mxGeometry x="350" y="100" width="120" height="80" as="geometry" />
</mxCell>

<!-- Diamond (decision) -->
<mxCell id="4" value="Check?" style="rhombus;whiteSpace=wrap;html=1;fillColor=#fff2cc;strokeColor=#d6b656;" vertex="1" parent="1">
  <mxGeometry x="100" y="220" width="160" height="80" as="geometry" />
</mxCell>

Containers and groups

For architecture diagrams with nested elements, use draw.io's parent-child containment — do not just place shapes on top of larger shapes.

group;pointerEvents=0;

swimlane;startSize=30;

container=1;pointerEvents=0;

Key rules:

• Add

  pointerEvents=0;

  to container styles that should not capture connections between children
• Children set

  parent="containerId"

  and use coordinates relative to the container

<!-- Swimlane container -->
<mxCell id="svc1" value="User Service" style="swimlane;startSize=30;fillColor=#dae8fc;strokeColor=#6c8ebf;" vertex="1" parent="1">
  <mxGeometry x="100" y="100" width="300" height="200" as="geometry"/>
</mxCell>
<!-- Child inside container — coordinates relative to parent -->
<mxCell id="api1" value="REST API" style="rounded=1;whiteSpace=wrap;html=1;" vertex="1" parent="svc1">
  <mxGeometry x="20" y="40" width="120" height="60" as="geometry"/>
</mxCell>
<mxCell id="db1" value="Database" style="shape=cylinder3;whiteSpace=wrap;html=1;" vertex="1" parent="svc1">
  <mxGeometry x="160" y="40" width="120" height="60" as="geometry"/>
</mxCell>

Connector (edge)

CRITICAL: Every edge

mxCell

<mxGeometry relative="1" as="geometry" />

<mxCell ... edge="1" ... />

<!-- Directed arrow — always include rounded, orthogonalLoop, jettySize for clean routing -->
<mxCell id="10" value="" style="edgeStyle=orthogonalEdgeStyle;rounded=1;orthogonalLoop=1;jettySize=auto;html=1;" edge="1" parent="1" source="2" target="3">
  <mxGeometry relative="1" as="geometry" />
</mxCell>

<!-- Arrow with label + explicit entry/exit points to control direction -->
<mxCell id="11" value="HTTP/REST" style="edgeStyle=orthogonalEdgeStyle;rounded=1;orthogonalLoop=1;jettySize=auto;html=1;exitX=0.5;exitY=1;exitDx=0;exitDy=0;entryX=0.5;entryY=0;entryDx=0;entryDy=0;" edge="1" parent="1" source="2" target="4">
  <mxGeometry relative="1" as="geometry" />
</mxCell>

<!-- Arrow with waypoints — use when edge must route around other shapes -->
<mxCell id="12" value="" style="edgeStyle=orthogonalEdgeStyle;rounded=1;orthogonalLoop=1;jettySize=auto;html=1;" edge="1" parent="1" source="3" target="5">
  <mxGeometry relative="1" as="geometry">
    <Array as="points">
      <mxPoint x="500" y="50" />
    </Array>
  </mxGeometry>
</mxCell>

Edge style rules:

• Animated connectors: add

  flowAnimation=1;

  to any edge style to show a moving dot animation along the arrow. Works in SVG export and draw.io desktop — ideal for data-flow and pipeline diagrams. Example:

  style="edgeStyle=orthogonalEdgeStyle;flowAnimation=1;rounded=1;..."

• Always include

  rounded=1;orthogonalLoop=1;jettySize=auto

  — these enable smart routing that avoids overlaps
• Pin

  exitX/exitY/entryX/entryY

  on every edge when a node has 2+ connections — distributes lines across the shape perimeter
• Add

  <Array as="points">

  waypoints when an edge must detour around an intermediate shape
• Leave room for arrowheads: the final straight segment between the last bend and the target shape must be ≥20px long. If too short, the arrowhead overlaps the bend and looks broken. Fix by increasing node spacing or adding explicit waypoints

Distributing connections on a shape

When multiple edges connect to the same shape, assign different entry/exit points to prevent stacking:

Rule: if a shape has N connections on one side, space them evenly (e.g., 3 connections on bottom → exitX = 0.25, 0.5, 0.75)

Color palette (fillColor / strokeColor)

#dae8fc

#6c8ebf

#d5e8d4

#82b366

#fff2cc

#d6b656

#ffe6cc

#d79b00

#f8cecc

#b85450

#f5f5f5

#666666

#e1d5e7

#9673a6

Layout tips

Spacing — scale with complexity:

Routing corridors: between shape rows/columns, leave an extra ~80px empty corridor where edges can route without crossing shapes. Never place a shape in a gap that edges need to traverse.

Grid alignment: snap all

x

y

width

height

General rules:

• Plan a grid before assigning x/y coordinates — sketch node positions on paper/mentally first
• Group related nodes in the same horizontal or vertical band
• Use

  swimlane

  cells for logical grouping with visible borders
• Place heavily-connected "hub" nodes centrally so edges radiate outward instead of crossing
• To force straight vertical connections, pin entry/exit points explicitly on edges:

  exitX=0.5;exitY=1;exitDx=0;exitDy=0;entryX=0.5;entryY=0;entryDx=0;entryDy=0

• Always center-align a child node under its parent (same center x) to avoid diagonal routing
• Event bus pattern: place Kafka/bus nodes in the center of the service row, not below — services on either side can reach it with short horizontal arrows (

  exitX=1

  left side,

  exitX=0

  right side), eliminating all line crossings
• Horizontal connections (

  exitX=1

  or

  exitX=0

  ) never cross vertical nodes in the same row; use them for peer-to-peer and publish connections

Avoiding edge-shape overlap:

• Before finalizing coordinates, trace each edge path mentally — if it must cross an unrelated shape, either move the shape or add waypoints
• For tree/hierarchical layouts: assign nodes to layers (rows), connect only between adjacent layers to minimize crossings
• For star/hub layouts: place the hub center, satellites around it — edges stay short and radial
• When an edge must span multiple rows/columns, route it along the outer corridor, not through the middle of the diagram

Export

Commands

# macOS — Homebrew (draw.io in PATH)
draw.io -x -f png -e -s 2 -o diagram.drawio.png input.drawio

# macOS — full path (if not in PATH)
/Applications/draw.io.app/Contents/MacOS/draw.io -x -f png -e -s 2 -o diagram.drawio.png input.drawio

# Windows
"C:\Program Files\draw.io\draw.io.exe" -x -f png -e -s 2 -o diagram.drawio.png input.drawio

# Linux (headless — requires xvfb-run)
xvfb-run -a draw.io -x -f png -e -s 2 -o diagram.drawio.png input.drawio

# SVG export
draw.io -x -f svg -o diagram.svg input.drawio

# PDF export
draw.io -x -f pdf -o diagram.pdf input.drawio

Key flags:

• -x

  — export mode (required)

• -f

  — format:

  png

  ,

  svg

  ,

  pdf

  ,

  jpg

• -e

  — embed diagram XML in output (PNG, SVG, PDF only) — exported file remains editable in draw.io

• -s

  — scale:

  1

  ,

  2

  ,

  3

  (2 recommended for PNG)

• -o

  — output file path (use

  .drawio.png

  double extension when embedding)

• -b

  — border width around diagram (default: 0, recommend 10)

• -t

  — transparent background (PNG only)

• --page-index 0

  — export specific page (default: all)

Browser fallback (no CLI needed)

When the draw.io desktop CLI is unavailable, generate a browser-editable URL by deflate-compressing and base64-encoding the XML:

# Encode .drawio XML into a diagrams.net URL
python3 -c "
import zlib, base64, urllib.parse, sys
xml = open(sys.argv[1]).read()
compressed = zlib.compress(xml.encode('utf-8'), 9)
encoded = base64.urlsafe_b64encode(compressed).decode('utf-8')
print('https://viewer.diagrams.net/?tags=%7B%7D&lightbox=1&edit=_blank#R' + urllib.parse.quote(encoded, safe=''))
" input.drawio

This produces a client-side URL that opens the diagram in the browser for viewing and editing. No data is uploaded to any server — the entire diagram XML is encoded in the URL fragment (after

#

Fallback chain

When tools are unavailable, degrade gracefully:

.drawio

xvfb-run -a

.drawio

Checking if draw.io is in PATH

# Try short command first
if command -v draw.io &>/dev/null; then
  DRAWIO="draw.io"
elif [ -f "/Applications/draw.io.app/Contents/MacOS/draw.io" ]; then
  DRAWIO="/Applications/draw.io.app/Contents/MacOS/draw.io"
else
  echo "draw.io not found — install from https://github.com/jgraph/drawio-desktop/releases"
fi

Common Mistakes

id="0"

id="1"

<root>

source

target

id

/Applications/draw.io.app/Contents/MacOS/draw.io

xvfb-run -a

--transparent

value

&

<

>

"

mxCell

<mxGeometry>

--

\n




value

Diagram Type Presets

When the user requests a specific diagram type, apply the matching preset below for shapes, styles, and layout conventions.

ERD (Entity-Relationship Diagram)

shape=table;startSize=30;container=1;collapsible=1;childLayout=tableLayout;fixedRows=1;rowLines=0;fontStyle=1;strokeColor=#6c8ebf;fillColor=#dae8fc;

shape=tableRow;horizontal=0;startSize=0;swimlaneHead=0;swimlaneBody=0;fillColor=none;collapsible=0;dropTarget=0;points=[[0,0.5],[1,0.5]];portConstraint=eastwest;fontSize=12;

parent=tableId

fontStyle=1

PK

dashed=1;endArrow=ERmandOne;startArrow=ERmandOne;

UML Class Diagram

swimlane;fontStyle=1;align=center;startSize=26;html=1;

line;strokeWidth=1;fillColor=none;align=left;verticalAlign=middle;spacingTop=-1;spacingLeft=3;spacingRight=10;rotatable=0;labelPosition=left;points=[];portConstraint=eastwest;

endArrow=block;endFill=0;

endArrow=block;endFill=0;dashed=1;

endArrow=diamondThin;endFill=1;

endArrow=diamondThin;endFill=0;

Sequence Diagram

shape=umlLifeline;perimeter=lifelinePerimeter;whiteSpace=wrap;html=1;container=1;collapsible=0;recursiveResize=0;outlineConnect=0;portConstraint=eastwest;

html=1;verticalAlign=bottom;endArrow=block;

html=1;verticalAlign=bottom;endArrow=open;dashed=1;

html=1;verticalAlign=bottom;endArrow=open;dashed=1;strokeColor=#999999;

shape=umlFrame;whiteSpace=wrap;

Architecture Diagram

swimlane;startSize=30;

rounded=1;whiteSpace=wrap;html=1;

shape=cylinder3;whiteSpace=wrap;html=1;

rounded=1;whiteSpace=wrap;html=1;fillColor=#fff2cc;strokeColor=#d6b656;

shape=mxgraph.aws4.resourceIcon;

rounded=1;

rounded=1;dashed=1;fillColor=#f5f5f5;strokeColor=#666666;

ML / Deep Learning Model Diagram

For neural network architecture diagrams — ideal for papers targeting NeurIPS, ICML, ICLR.

rounded=1;whiteSpace=wrap;html=1;

fillColor=#d5e8d4;strokeColor=#82b366;

fillColor=#dae8fc;strokeColor=#6c8ebf;

fillColor=#e1d5e7;strokeColor=#9673a6;

fillColor=#fff2cc;strokeColor=#d6b656;

fillColor=#ffe6cc;strokeColor=#d79b00;

fillColor=#f8cecc;strokeColor=#b85450;

dashed=1;endArrow=block;curved=1;

value="Conv2D
(B, 64, 32, 32)"




Tensor shape convention: annotate each layer with input/output tensor dimensions in

(B, C, H, W)

(B, T, D)




Flowchart (enhanced)

ellipse;whiteSpace=wrap;html=1;fillColor=#d5e8d4;strokeColor=#82b366;

rounded=0;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;

rhombus;whiteSpace=wrap;html=1;fillColor=#fff2cc;strokeColor=#d6b656;

shape=parallelogram;perimeter=parallelogramPerimeter;whiteSpace=wrap;html=1;fillColor=#ffe6cc;strokeColor=#d79b00;

rounded=0;whiteSpace=wrap;html=1;fillColor=#e1d5e7;strokeColor=#9673a6;

value="Yes"

value="No"