aws-architecture-diagram

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# AWS Architecture Diagram Skill

Generate AWS architecture diagrams as native `.drawio` files using official AWS Architecture Icons. Optionally export to PNG, SVG, or PDF with embedded XML (so exported files remain editable in draw.io).

## How to create a diagram

1. **Generate draw.io XML** in mxGraphModel format following the rules below
2. **Write the XML** to a `.drawio` file using the Write tool
3. **If the user requested an export format** (png, svg, pdf), export using the draw.io CLI (see Export section)
4. **Open the result** with `open` (macOS), `xdg-open` (Linux), or print the path

## Layout Rules

- **Left-to-right flow** for data/request path
- **UI/Frontend on the LEFT** (users access from left side)
- **Data sources / external systems on the RIGHT**
- Use horizontal lanes for parallel paths (top lane, bottom lane)
- **Minimum 220px horizontal spacing** between icons (room for edge labels)
- **Minimum 250px vertical spacing** between lanes
- Secondary/auxiliary services (monitoring, DLQ) go BELOW main flow with 280px+ gap
- Canvas: `pageWidth="2400" pageHeight="1400"`, viewport `dx="2800" dy="1600"`
- Always include a title block after the background rectangle:
```xml
<mxCell value="&lt;b&gt;Diagram Title&lt;/b&gt;&lt;br&gt;Author | Date | Version" style="text;html=1;align=left;verticalAlign=top;whiteSpace=wrap;rounded=0;fontSize=14;spacing=8;" vertex="1" parent="1">
  <mxGeometry x="40" y="30" width="420" height="60" as="geometry" />
</mxCell>
```

## Icon Style

- Icons are from draw.io's built-in `mxgraph.aws4` stencil library — the **official AWS Architecture Icons** (https://aws.amazon.com/architecture/icons/)
- Icon size: **78x78px** for main services, **65x65px** for secondary
- Use `sketch=0` on all icons
- Use `strokeColor=#ffffff` on all AWS service icons
- Font size: **12px** for labels
- **NO colored backgrounds** on group boxes — always `fillColor=none`

### 3D / Isometric Diagrams — use a different icon library
If the user asks for a **3D**, **isometric**, or "AWS 3D" diagram, do NOT fake it by placing flat `aws4` icons on hand-built platform/pedestal shapes. draw.io has a real, separate built-in library for this: `mxgraph.aws3d.*`.
- Load `references/aws-icons-3d.md` before picking any icon — it has the verified shape table, style prefix, sizes, and the native `isometricEdgeStyle` edge templates.
- This library is a legacy pre-2019 icon set with **much smaller coverage** than `aws4` (no API Gateway, ECS/EKS/Fargate, Step Functions, EventBridge, SNS, Aurora, CloudWatch, IAM, etc.). Check the gap table in that reference file before assuming an icon exists, and flag substitutions to the user rather than guessing a stencil name.
- For generic hardware (clients, on-prem servers, racks, switches) with no AWS-specific icon, see `references/aws-icons-allied-telesis.md` — a separate bundled isometric image library that fills that gap.
- These icons are already 3D on their own — arrange them in an ascending isometric staircase (diagonal offsets between nodes), don't add fake platforms underneath.
- Use `edgeStyle=isometricEdgeStyle` (with `endArrow=block` override for reliable arrowheads) instead of `orthogonalEdgeStyle` for connectors.

## Edge Style — CRITICAL FOR CLEAN DIAGRAMS

**Base edge style:**
```
edgeStyle=orthogonalEdgeStyle;rounded=1;orthogonalLoop=1;jettySize=auto;html=1;strokeWidth=2;exitX=1;exitY=0.5;exitDx=0;exitDy=0;entryX=0;entryY=0.5;entryDx=0;entryDy=0;
```

**Edge label rules:**
- Keep labels SHORT (1-2 words max). Detail goes in icon labels, not edge labels.
- Always add `labelBackgroundColor=#F5F5F5;fontSize=11;` to edges with labels
- For edges WITHOUT labels: omit `value` entirely
- When NOT to label: if the flow is obvious (Lambda → DynamoDB doesn't need "Write")

**For edges to services ABOVE or BELOW main flow, use explicit exit/entry points:**
- Exit bottom: `exitX=0.5;exitY=1;exitDx=0;exitDy=0;`
- Enter top: `entryX=0.5;entryY=0;entryDx=0;entryDy=0;`
- This prevents draw.io from routing lines through other icons

**Edge types:**
- Solid (`strokeWidth=2`): primary data flow
- Dashed (`strokeWidth=2;dashed=1;`): optional/async
- Red dashed (`strokeWidth=2;dashed=1;strokeColor=#DD344C;`): error path

**Edge attachment (CRITICAL — fixes "green cross" problem):**
- Every edge MUST have both `source="<cell-id>"` and `target="<cell-id>"` attributes referencing valid cell IDs
- NEVER create floating/unattached edges — all edges must be bound to shapes at both ends
- Always include `exitX/exitY` and `entryX/entryY` to define exact connection points on the shape perimeter
- **Cross-container edges:** When source and target are in different containers, set the edge's `parent="1"`

## Visual Quality: straight arrows, no overlaps, professional layout

A diagram with correct icons but a messy layout still reads as unprofessional. Check every diagram against these rules before finishing — they're deliberately concrete/checkable, not vague "make it look nice" advice:

- **Align nodes to a consistent axis so edges are single, straight segments.** Keep the horizontal or vertical delta between adjacent nodes in a flow constant (same lane y-coordinate, same column spacing) so connecting edges render as one clean line instead of a dogleg.
- **Align branch/secondary nodes on the exact same centerline as their parent.** If a node branches off vertically (e.g. an auxiliary service below the main flow), its horizontal center must match its parent's horizontal center exactly — compute `child.x = parent.center_x - child.width/2`, don't eyeball it. A few pixels of misalignment turns a "straight down" edge into a visibly crooked diagonal.
- **One bend maximum per edge, ideally zero.** If a computed edge path would need more than one bend to avoid an obstacle, the layout is wrong — move the node, don't add more bends to route around the problem.
- **No edge may cross through an unrelated icon's bounding box.** Before finalizing coordinates, check each edge's path against every icon's `(x, y, width, height)` rectangle it isn't connected to. If it would cross one, move the node or add an explicit exit/entry point to route around it.
- **No two edges may run on top of each other or visually merge.** If two edges would travel the same corridor (e.g. two parallel flows between the same pair of lanes), offset them — different exit/entry points, or an explicit waypoint — so there's a visible gap between them.
- **Minimize edge crossings overall.** Order nodes in the direction the data actually flows so edges rarely need to cross each other. If a crossing is unavoidable (e.g. a feedback/response path), route it with a visible offset rather than letting it overlap another edge.
- **Keep spacing consistent, not just "enough."** Use the same minimum step size between every pair of adjacent nodes in a flow — a diagram where some gaps are 400px and others are 250px reads as sloppy even if nothing technically overlaps.
- **Balance the composition on the canvas.** Don't leave one half of the page dense and the other empty; size the canvas to the actual content plus a consistent margin.
- **Self-check before finishing:** after placing every coordinate, mentally trace each edge from source to target and verify (1) it doesn't cross any icon, (2) it doesn't overlap another edge, (3) it has at most one bend, (4) its endpoints are flush with the icons it connects. Fix the layout, not just the intent, if any check fails.

## PNG Export Background
First element after root cells (lowest z-order):
```xml
<mxCell value="" style="rounded=0;whiteSpace=wrap;html=1;fillColor=#F5F5F5;strokeColor=none;" vertex="1" parent="1">
  <mxGeometry x="0" y="0" width="2400" height="1400" as="geometry" />
</mxCell>
```

## AWS Icon Patterns (VERIFIED WORKING)

### resourceIcon (78x78, colored square frame)

| Service | resIcon | fillColor |
|---------|---------|-----------|
| Lambda | `mxgraph.aws4.lambda` | `#ED7100` |
| API Gateway | `mxgraph.aws4.api_gateway` | `#E7157B` |
| EventBridge | `mxgraph.aws4.eventbridge` | `#E7157B` |
| SNS | `mxgraph.aws4.sns` | `#E7157B` |
| SES | `mxgraph.aws4.simple_email_service` | `#DD344C` |
| Step Functions | `mxgraph.aws4.step_functions` | `#E7157B` |
| DynamoDB | `mxgraph.aws4.dynamodb` | `#C925D1` |
| RDS | `mxgraph.aws4.rds` | `#C925D1` |
| S3 | `mxgraph.aws4.s3` | `#7AA116` |
| CloudFront | `mxgraph.aws4.cloudfront` | `#8C4FFF` |
| Route 53 | `mxgraph.aws4.route_53` | `#8C4FFF` |
| ECS | `mxgraph.aws4.ecs` | `#ED7100` |
| EC2 | `mxgraph.aws4.ec2` | `#ED7100` |

Style template:
```
sketch=0;points=[[0,0,0],[0.25,0,0],[0.5,0,0],[0.75,0,0],[1,0,0],[0,1,0],[0.25,1,0],[0.5,1,0],[0.75,1,0],[1,1,0],[0,0.25,0],[0,0.5,0],[0,0.75,0],[1,0.25,0],[1,0.5,0],[1,0.75,0]];outlineConnect=0;fontColor=#232F3E;fillColor=<COLOR>;strokeColor=#ffffff;dashed=0;verticalLabelPosition=bottom;verticalAlign=top;align=center;html=1;fontSize=12;fontStyle=0;aspect=fixed;shape=mxgraph.aws4.resourceIcon;resIcon=mxgraph.aws4.<SERVICE>

From vidanov/aws-architecture-diagram-skill, MIT.

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