excalidraw

name	excalidraw
description	Generate architecture diagrams as .excalidraw files from codebase analysis, with optional PNG/SVG export. Use when the user asks to create architecture diagrams, system diagrams, visualize codebase structure, generate excalidraw files, export excalidraw diagrams to PNG or SVG, or convert .excalidraw files to image formats.

Excalidraw Diagram Generator

Generate architecture diagrams as .excalidraw files directly from codebase analysis, with optional export to PNG and SVG.

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Quick Start

User just asks:

"Generate an architecture diagram for this project"
"Create an excalidraw diagram of the system"
"Visualize this codebase as an excalidraw file"

Claude Code will:

1. Analyze the codebase (any language/framework)
2. Identify components, services, databases, APIs
3. Map relationships and data flows
4. Generate valid .excalidraw JSON with dynamic IDs and labels
5. Optionally export to PNG and/or SVG using Playwright

No prerequisites: Works without existing diagrams, Terraform, or specific file types.

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Critical Rules

1. NEVER Use Diamond Shapes

Diamond arrow connections are broken in raw Excalidraw JSON. Use styled rectangles instead:

Semantic Meaning	Rectangle Style
Orchestrator/Hub	Coral (#ffa8a8/#c92a2a) + strokeWidth: 3
Decision Point	Orange (#ffd8a8/#e8590c) + dashed stroke

2. Labels Require TWO Elements

The label property does NOT work in raw JSON. Every labeled shape needs:

// 1. Shape with boundElements reference
{
  "id": "my-box",
  "type": "rectangle",
  "boundElements": [{ "type": "text", "id": "my-box-text" }]
}

// 2. Separate text element with containerId
{
  "id": "my-box-text",
  "type": "text",
  "containerId": "my-box",
  "text": "My Label"
}

3. Elbow Arrows Need Three Properties

For 90-degree corners (not curved):

{
  "type": "arrow",
  "roughness": 0,        // Clean lines
  "roundness": null,     // Sharp corners
  "elbowed": true        // 90-degree mode
}

4. Arrow Edge Calculations

Arrows must start/end at shape edges, not centers:

Edge	Formula
Top	(x + width/2, y)
Bottom	(x + width/2, y + height)
Left	(x, y + height/2)
Right	(x + width, y + height/2)

Detailed arrow routing: See references/arrows.md

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Element Types

Type	Use For
rectangle	Services, databases, containers, orchestrators
ellipse	Users, external systems, start/end points
text	Labels inside shapes, titles, annotations
arrow	Data flow, connections, dependencies
line	Grouping boundaries, separators

Full JSON format: See references/json-format.md

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Workflow

Step 1: Analyze Codebase

Discover components by looking for:

Codebase Type	What to Look For
Monorepo	packages/*/package.json, workspace configs
Microservices	docker-compose.yml, k8s manifests
IaC	Terraform/Pulumi resource definitions
Backend API	Route definitions, controllers, DB models
Frontend	Component hierarchy, API calls

Use tools:

• Glob → **/package.json, **/Dockerfile, **/*.tf
• Grep → app.get, @Controller, CREATE TABLE
• Read → README, config files, entry points

Step 2: Plan Layout

Vertical flow (most common):

Row 1: Users/Entry points (y: 100)
Row 2: Frontend/Gateway (y: 230)
Row 3: Orchestration (y: 380)
Row 4: Services (y: 530)
Row 5: Data layer (y: 680)

Columns: x = 100, 300, 500, 700, 900
Element size: 160-200px x 80-90px

Other patterns: See references/examples.md

Step 3: Generate Elements

For each component:

1. Create shape with unique id
2. Add boundElements referencing text
3. Create text with containerId
4. Choose color based on type

Color palettes: See references/colors.md

Step 4: Add Connections

For each relationship:

1. Calculate source edge point
2. Plan elbow route (avoid overlaps)
3. Create arrow with points array
4. Match stroke color to destination type

Arrow patterns: See references/arrows.md

Step 5: Add Grouping (Optional)

For logical groupings:

• Large transparent rectangle with strokeStyle: "dashed"
• Standalone text label at top-left

Step 6: Validate and Write

Run validation before writing. Save to docs/ or user-specified path.

Validation checklist: See references/validation.md

Step 7: Export to PNG/SVG (Optional)

After writing the .excalidraw file, ask the user if they want PNG, SVG, or both exports.

Uses Playwright MCP tools and @excalidraw/utils to programmatically render the diagram — no manual upload to excalidraw.com needed.

Requires: Playwright MCP tools (browser_navigate, browser_run_code, browser_close).

Full export procedure: See references/export.md

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Quick Arrow Reference

Straight down:

{ "points": [[0, 0], [0, 110]], "x": 590, "y": 290 }

L-shape (left then down):

{ "points": [[0, 0], [-325, 0], [-325, 125]], "x": 525, "y": 420 }

U-turn (callback):

{ "points": [[0, 0], [50, 0], [50, -125], [20, -125]], "x": 710, "y": 440 }

Arrow width/height = bounding box of points:

points [[0,0], [-440,0], [-440,70]] → width=440, height=70

Multiple arrows from same edge - stagger positions:

5 arrows: 20%, 35%, 50%, 65%, 80% across edge width

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Default Color Palette

Component	Background	Stroke
Frontend	#a5d8ff	#1971c2
Backend/API	#d0bfff	#7048e8
Database	#b2f2bb	#2f9e44
Storage	#ffec99	#f08c00
AI/ML	#e599f7	#9c36b5
External APIs	#ffc9c9	#e03131
Orchestration	#ffa8a8	#c92a2a
Message Queue	#fff3bf	#fab005
Cache	#ffe8cc	#fd7e14
Users	#e7f5ff	#1971c2

Cloud-specific palettes: See references/colors.md

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Quick Validation Checklist

Before writing file:

• Every shape with label has boundElements + text element
• Text elements have containerId matching shape
• Multi-point arrows have elbowed: true, roundness: null
• Arrow x,y = source shape edge point
• Arrow final point offset reaches target edge
• No diamond shapes
• No duplicate IDs

Full validation algorithm: See references/validation.md

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Common Issues

Issue	Fix
Labels don't appear	Use TWO elements (shape + text), not label property
Arrows curved	Add elbowed: true, roundness: null, roughness: 0
Arrows floating	Calculate x,y from shape edge, not center
Arrows overlapping	Stagger start positions across edge

Detailed bug fixes: See references/validation.md

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Reference Files

File	Contents
references/json-format.md	Element types, required properties, text bindings
references/arrows.md	Routing algorithm, patterns, bindings, staggering
references/colors.md	Default, AWS, Azure, GCP, K8s palettes
references/examples.md	Complete JSON examples, layout patterns
references/validation.md	Checklists, validation algorithm, bug fixes
references/export.md	PNG/SVG export procedure via Playwright

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Output

• Location: docs/architecture/ or user-specified
• Filename: Descriptive, e.g., system-architecture.excalidraw
• Exports (optional): system-architecture.svg and/or system-architecture.png in same directory
• Testing: Open .excalidraw in https://excalidraw.com or VS Code extension; .svg and .png can be viewed directly or embedded in documentation