Drawio Logical Diagrams

---
name: drawio-logical-diagrams
description: 'Creates professional logical flow diagrams and logical system architecture diagrams using draw.io XML format (.drawio files). Use when creating: (1) logical flow diagrams showing data/process flow between system components, (2) logical architecture diagrams representing system structure without cloud provider specifics, (3) BPMN process diagrams, (4) UML diagrams (class, sequence, activity), (5) data flow diagrams (DFD), (6) decision flowcharts, or (7) system interaction diagrams. This skill focuses on generic/abstract representations, not AWS/Azure-specific architectures (use aws-drawio-architecture-diagrams for cloud diagrams).'
allowed-tools: Read, Write, Bash
---

# Draw.io Logical Diagrams Creation

## Overview

Create professional logical diagrams in draw.io's native XML format for logical flow diagrams, system architecture visualizations, and abstract process representations using generic shapes and symbols.

## When to Use

- Creating logical flow diagrams showing data flow between system components
- Designing logical architecture diagrams (abstract system structure)
- Building BPMN process diagrams for business processes
- Drawing UML diagrams (class, sequence, activity, state)
- Creating data flow diagrams (DFD) for system analysis
- Making decision flowcharts with branching logic
- Visualizing system interactions and sequences
- Documenting logical system design without cloud specifics

**Do NOT use for:** AWS/Azure/GCP architecture diagrams (use `aws-drawio-architecture-diagrams`).

## Instructions

### Creating a Logical Diagram

1. **Analyze the request**: Understand the system/process to diagram
2. **Choose diagram type**: Flowchart, architecture, BPMN, UML, DFD, etc.
3. **Identify elements**: Determine actors, processes, data stores, connectors
4. **Draft XML structure**: Create the mxGraphModel with proper root cells
5. **Add shapes**: Create mxCell elements with appropriate styles
6. **Add connectors**: Link elements with edge elements
7. **Validate XML**: Verify XML is well-formed and all IDs are unique (see validation checklist below)
8. **Output**: Write the .drawio file for the user

### XML Validation Checklist

Before outputting the file, verify:
- [ ] All tags are properly closed (no unclosed `<mxCell>`, `</mxGeometry>`, etc.)
- [ ] All cell IDs are unique (0 and 1 are reserved root cells, use sequential integers starting from 2)
- [ ] All `source` and `target` attributes reference existing cell IDs
- [ ] All `parent` attributes reference existing cell IDs
- [ ] All coordinates (x, y, width, height) are positive numbers
- [ ] Special characters are escaped (`<` → `&lt;`, `>` → `&gt;`, `&` → `&amp;`)
- [ ] Multi-line labels use `&#xa;` or `<br>` with `html=1` in style

### Key XML Components

| Component | Description |
|-----------|-------------|
| `mxfile` | Root element with host and version |
| `diagram` | Contains the diagram definition |
| `mxGraphModel` | Canvas settings (grid, page size) |
| `root` | Container for all cells (must include id="0" and id="1") |
| `mxCell` | Individual shapes (vertices) or connectors (edges) |

## Draw.io XML Structure

```xml
<mxfile host="app.diagrams.net" agent="Claude" version="24.7.17">
  <diagram id="logical-flow-1" name="Logical Flow">
    <mxGraphModel dx="1200" dy="800" grid="1" gridSize="10" guides="1"
      tooltips="1" connect="1" arrows="1" fold="1" page="1"
      pageScale="1" pageWidth="1169" pageHeight="827" math="0" shadow="0">
      <root>
        <mxCell id="0" />
        <mxCell id="1" parent="0" />
        <!-- Shapes and connectors here -->
      </root>
    </mxGraphModel>
  </diagram>
</mxfile>
```

**Key rules:**
- IDs "0" and "1" are reserved for root cells
- Use sequential integer IDs starting from "2"
- Use landscape orientation for architecture diagrams
- All coordinates must be positive and aligned to grid (multiples of 10)

## Generic Shapes and Styles

### Basic Shape Types

| Shape | Style |
|-------|-------|
| Rectangle | `rounded=0;whiteSpace=wrap;html=1;` |
| Rounded Rectangle | `rounded=1;whiteSpace=wrap;html=1;` |
| Ellipse/Circle | `ellipse;whiteSpace=wrap;html=1;` |
| Diamond | `rhombus;whiteSpace=wrap;html=1;` |
| Cylinder | `shape=cylinder3;whiteSpace=wrap;html=1;boundedLbl=1;` |
| Hexagon | `shape=hexagon;perimeter=hexagonPerimeter2;whiteSpace=wrap;html=1;` |
| Parallelogram | `shape=ext;double=1;rounded=0;whiteSpace=wrap;html=1;` |

### Standard Color Palette

| Element Type | Fill Color | Border Color | Usage |
|--------------|------------|--------------|-------|
| Process | `#dae8fc` | `#6c8ebf` | Operations/actions |
| Decision | `#fff2cc` | `#d6b656` | Conditional branches |
| Start/End | `#d5e8d4` | `#82b366` | Terminal states |
| Data/Store | `#e1f5fe` | `#0277bd` | Databases/files |
| Entity | `#f3e5f5` | `#7b1fa2` | External systems |
| Error/Stop | `#f8cecc` | `#b85450` | Error states |
| Actor/User | `#ffe0b2` | `#f57c00` | Users/actors |
| Container | `#f5f5f5` | `#666666` | Grouping areas |

### Connector Styles

**Standard flow:**
```
edgeStyle=orthogonalEdgeStyle;rounded=0;orthogonalLoop=1;jettySize=auto;html=1;endArrow=classic;endFill=1;strokeColor=#666666;strokeWidth=2;
```

**Dashed (alternative/optional):**
```
edgeStyle=orthogonalEdgeStyle;dashed=1;dashPattern=5 5;strokeColor=#666666;
```

**Arrow head styles:**
- `endArrow=classic;endFill=1` - Filled triangle
- `endArrow=open;endFill=0` - Open arrow
- `endArrow=blockThin;endFill=1` - Block arrow

## Diagram Types

| Type | Key Elements |
|------|--------------|
| Logical Flow | Actors (orange), Services (blue), Data Stores (cyan), External Systems (purple) |
| Logical Architecture | Layered containers with nested components |
| BPMN | Circle (Start/End), Rounded Rectangle (Activity), Diamond (Gateway) |
| UML Sequence | Vertical lifelines with message arrows |
| DFD | Square (Entity), Circle (Process), Open Rectangle (Data Store) |

## Reference Files

For detailed shape examples and style references, see:
- [shape-styles.md](references/shape-styles.md) - Complete shape examples and style reference
- [diagram-templates.md](references/diagram-templates.md) - Ready-to-use templates

## Examples

### Example 1: Order Processing Flow

**Request:** "Create a logical flow diagram showing order processing: customer submits order, system validates, if valid then processes payment and ships, if invalid notifies customer."

```xml
<mxfile host="app.diagrams.net" agent="Claude" version="24.7.17">
  <diagram id="order-flow-1" name="Order Processing">
    <mxGraphModel dx="1200" dy="800" grid="1" gridSize="10" guides="1" tooltips="1" connect="1" arrows="1" fold="1" page="1" pageScale="1" pageWidth="1169" pageHeight="827" math="0" shadow="0">
      <root>
        <mxCell id="0"/><mxCell id="1" parent="0"/>
        <mxCell id="2" value="Start" style="ellipse;whiteSpace=wrap;html=1;fillColor=#d5e8d4;strokeColor=#82b366;fontSize=12;" vertex="1" parent="1"><mxGeometry x="80" y="50" width="80" height="40" as="geometry"/></mxCell>
        <mxCell id="3" value="Submit Order" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontSize=12;" vertex="1" parent="1"><mxGeometry x="60" y="130" width="120" height="60" as="geometry"/></mxCell>
        <mxCell id="4" value="Validate&#xa;Order?" style="rhombus;whiteSpace=wrap;html=1;fillColor=#fff2cc;strokeColor=#d6b656;fontSize=12;" vertex="1" parent="1"><mxGeometry x="80" y="230" width="80" height="80" as="geometry"/></mxCell>
        <mxCell id="5" value="Notify&#xa;Customer" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#f8cecc;strokeColor=#b85450;fontSize=12;" vertex="1" parent="1"><mxGeometry x="220" y="240" width="100" height="50" as="geometry"/></mxCell>
        <mxCell id="6" value="Process&#xa;Payment" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontSize=12;" vertex="1" parent="1"><mxGeometry x="60" y="350" width="120" height="60" as="geometry"/></mxCell>
        <mxCell id="7" value="Ship Order" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontSize=12;" vertex="1" parent="1"><mxGeometry x="60" y="450" width="120" height="60" as="geometry"/></mxCell>
        <mxCell id="8" value="End" style="ellipse;whiteSpace=wrap;html=1;fillColor=#d5e8d4;strokeColor=#82b366;fontSize=12;" vertex="1" parent="1"><mxGeometry x="80" y="550" width="80" height="40" as="geometry"/></mxCell>
        <mxCell id="10" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#666666;strokeWidth=2;" edge="1" parent="1" source="2" target="3"><mxGeometry relative="1" as="geometry"/></mxCell>
        <mxCell id="11" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#666666;strokeWidth=2;" edge="1" parent="1" source="3" target="4"><mxGeometry relative="1" as="geometry"/></mxCell>
        <mxCell id="12" value="No" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#b85450;strokeWidth=2;fontSize=11;" edge="1" parent="1" source="4" target="5"><mxGeometry relative="1" as="geometry"/></mxCell>
        <mxCell id="13" value="Yes" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#82b366;strokeWidth=2;fontSize=11;" edge="1" parent="1" source="4" target="6"><mxGeometry relative="1" as="geometry"/></mxCell>
        <mxCell id="14" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#666666;strokeWidth=2;" edge="1" parent="1" source="6" target="7"><mxGeometry relative="1" as="geometry"/></mxCell>
        <mxCell id="15" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#666666;strokeWidth=2;" edge="1" parent="1" source="7" target="8"><mxGeometry relative="1" as="geometry"/></mxCell>
        <mxCell id="16" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#b85450;strokeWidth=2;" edge="1" parent="1" source="5" target="8"><mxGeometry relative="1" as="geometry"/></mxCell>
      </root>
    </mxGraphModel>
  </diagram>
</mxfile>
```

### Example 2: Three-Tier Logical Architecture

**Request:** "Create a logical architecture diagram for a web application with presentation, business logic, and data tiers."

```xml
<mxfile host="app.diagrams.net" agent="Claude" version="24.7.17">
  <diagram id="three-tier-1" name="Three-Tier Architecture">
    <mxGraphModel dx="1200" dy="800" grid="1" gridSize="10" guides="1" tooltips="1" connect="1" arrows="1" fold="1" page="1" pageScale="1" pageWidth="1169" pageHeight="827" math="0" shadow="0">
      <root>
        <mxCell id="0"/><mxCell id="1" parent="0"/>
        <mxCell id="2" value="User" style="ellipse;whiteSpace=wrap;html=1;fillColor=#ffe0b2;strokeColor=#f57c00;fontSize=12;" vertex="1" parent="1"><mxGeometry x="40" y="340" width="60" height="40" as="geometry"/></mxCell>
        <mxCell id="3" value="Presentation Layer" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#f5f5f5;strokeColor=#666666;fontSize=14;fontStyle=1;" vertex="1" parent="1"><mxGeometry x="160" y="40" width="300" height="180" as="geometry"/></mxCell>
        <mxCell id="4" value="Web&#xa;Browser" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontSize=12;" vertex="1" parent="3"><mxGeometry x="20" y="30" width="80" height="50" as="geometry"/></mxCell>
        <mxCell id="5" value="Mobile&#xa;App" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontSize=12;" vertex="1" parent="3"><mxGeometry x="120" y="30" width="80" height="50" as="geometry"/></mxCell>
        <mxCell id="7" value="Application Layer" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#f5f5f5;strokeColor=#666666;fontSize=14;fontStyle=1;" vertex="1" parent="1"><mxGeometry x="160" y="260" width="300" height="180" as="geometry"/></mxCell>
        <mxCell id="8" value="API&#xa;Gateway" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#fff2cc;strokeColor=#d6b656;fontSize=12;" vertex="1" parent="7"><mxGeometry x="20" y="30" width="80" height="50" as="geometry"/></mxCell>
        <mxCell id="9" value="Business&#xa;Logic" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontSize=12;" vertex="1" parent="7"><mxGeometry x="110" y="30" width="80" height="50" as="geometry"/></mxCell>
        <mxCell id="11" value="Data Layer" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#f5f5f5;strokeColor=#666666;fontSize=14;fontStyle=1;" vertex="1" parent="1"><mxGeometry x="160" y="480" width="300" height="180" as="geometry"/></mxCell>
        <mxCell id="12" value="Primary&#xa;Database" style="shape=cylinder3;whiteSpace=wrap;html=1;boundedLbl=1;fillColor=#e1f5fe;strokeColor=#0277bd;fontSize=12;" vertex="1" parent="11"><mxGeometry x="20" y="30" width="60" height="80" as="geometry"/></mxCell>
        <mxCell id="13" value="Cache" style="shape=cylinder3;whiteSpace=wrap;html=1;boundedLbl=1;fillColor=#fff3e0;strokeColor=#e65100;fontSize=12;" vertex="1" parent="11"><mxGeometry x="100" y="30" width="60" height="80" as="geometry"/></mxCell>
        <mxCell id="20" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#666666;strokeWidth=2;" edge="1" parent="1" source="2" target="4"><mxGeometry relative="1" as="geometry"/></mxCell>
        <mxCell id="21" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#666666;strokeWidth=2;" edge="1" parent="1" source="4" target="8"><mxGeometry relative="1" as="geometry"/></mxCell>
        <mxCell id="22" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#666666;strokeWidth=2;" edge="1" parent="1" source="8" target="9"><mxGeometry relative="1" as="geometry"/></mxCell>
        <mxCell id="23" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=classic;endFill=1;strokeColor=#666666;strokeWidth=2;" edge="1" parent="1" source="9" target="12"><mxGeometry relative="1" as="geometry"/></mxCell>
        <mxCell id="24" value="query" style="edgeStyle=orthogonalEdgeStyle;rounded=0;endArrow=open;endFill=0;strokeColor=#666666;strokeWidth=1;fontSize=10;dashed=1;" edge="1" parent="1" source="9" target="13"><mxGeometry relative="1" as="geometry"/></mxCell>
      </root>
    </mxGraphModel>
  </diagram>
</mxfile>
```

For additional templates (microservice architecture, event-driven, decision tree, sequence, DFD), see [diagram-templates.md](references/diagram-templates.md).

## Constraints and Warnings

### Critical Constraints

1. **XML validity**: Always close tags properly and escape special characters
2. **Unique IDs**: All cell IDs must be unique (except parent "0" and "1")
3. **Valid references**: Source/target must reference existing cell IDs
4. **Positive coordinates**: All x, y values must be >= 0

### Warnings

- XML files must be well-formed or will fail to open in draw.io
- Invalid parent references cause elements to disappear
- Negative coordinates place elements outside visible canvas

## Best Practices

1. Use consistent colors per element type across all diagrams
2. Keep arrows straight with minimal bends
3. Place labels at least 20px from arrow lines
4. Group related elements in containers
5. Use 12-14px font for labels, 10-11px for annotations
6. Align all coordinates to grid (multiples of 10)
7. Use high contrast colors and don't rely solely on color for meaning