Arch Diagram

Architecture Diagram Skill

Generate professional, dark-themed technical architecture diagrams as standalone HTML files with inline SVG graphics. No external tools, no API keys, no rendering libraries — just write the HTML file and open it in a browser.

Scope

Best suited for:

• Software system architecture (frontend / backend / database layers)
• Cloud infrastructure (VPC, regions, subnets, managed services)
• Microservice / service-mesh topology
• Database + API map, deployment diagrams
• Anything with a tech-infra subject that fits a dark, grid-backed aesthetic

Look elsewhere first for:

• Physics, chemistry, math, biology, or other scientific subjects
• Physical objects (vehicles, hardware, anatomy, cross-sections)
• Floor plans, narrative journeys, educational / textbook-style visuals
• Hand-drawn whiteboard sketches (consider excalidraw)
• Animated explainers (consider an animation skill)

If a more specialized skill is available for the subject, prefer that. If none fits, this skill can also serve as a general SVG diagram fallback — the output will just carry the dark tech aesthetic described below.

Based on Cocoon AI's architecture-diagram-generator (MIT).

Workflow

1. User describes their system architecture (components, connections, technologies)
2. Generate the HTML file following the design system below
3. Save with write_file to a .html file (e.g. ~/arch-diagram.html)
4. User opens in any browser — works offline, no dependencies

Output Location

Save diagrams to a user-specified path, or default to the current working directory:

./[project-name]-architecture.html

Preview

After saving, suggest the user open it:

# macOS
open ./my-architecture.html
# Linux
xdg-open ./my-architecture.html

Design System & Visual Language

Color Palette (Semantic Mapping)

Use specific rgba fills and hex strokes to categorize components:

Typography & Background

• Font: JetBrains Mono (Monospace), loaded from Google Fonts
• Sizes: 12px (Names), 9px (Sublabels), 8px (Annotations), 7px (Tiny labels)
• Background: Slate-950 (#020617) with a subtle 40px grid pattern

<!-- Background Grid Pattern -->
<pattern id="grid" width="40" height="40" patternUnits="userSpaceOnUse">
  <path d="M 40 0 L 0 0 0 40" fill="none" stroke="#1e293b" stroke-width="0.5"/>
</pattern>

Technical Implementation Details

Component Rendering

Components are rounded rectangles (rx="6") with 1.5px strokes. To prevent arrows from showing through semi-transparent fills, use a double-rect masking technique:

1. Draw an opaque background rect (#0f172a)
2. Draw the semi-transparent styled rect on top

Connection Rules

• Z-Order: Draw arrows early in the SVG (after the grid) so they render behind component boxes
• Arrowheads: Defined via SVG markers
• Security Flows: Use dashed lines in rose color (#fb7185)
• Boundaries:
  • Security Groups: Dashed (4,4), rose color
  • Regions: Large dashed (8,4), amber color, rx="12"

Spacing & Layout Logic

• Standard Height: 60px (Services); 80-120px (Large components)
• Vertical Gap: Minimum 40px between components
• Message Buses: Must be placed in the gap between services, not overlapping them
• Legend Placement: CRITICAL. Must be placed outside all boundary boxes. Calculate the lowest Y-coordinate of all boundaries and place the legend at least 20px below it.

Document Structure

The generated HTML file follows a four-part layout:

1. Header: Title with a pulsing dot indicator and subtitle
2. Main SVG: The diagram contained within a rounded border card
3. Summary Cards: A grid of three cards below the diagram for high-level details
4. Footer: Minimal metadata

Info Card Pattern

<div class="card">
  <div class="card-header">
    <div class="card-dot cyan"></div>
    <h3>Title</h3>
  </div>
  <ul>
    <li>• Item one</li>
    <li>• Item two</li>
  </ul>
</div>

Output Requirements

• Single File: One self-contained .html file
• No External Dependencies: All CSS and SVG must be inline (except Google Fonts)
• No JavaScript: Use pure CSS for any animations (like pulsing dots)
• Compatibility: Must render correctly in any modern web browser

Template Reference

Load the full HTML template for the exact structure, CSS, and SVG component examples:

skill_view(name="arch-diagram", file_path="templates/template.html")

The template contains working examples of every component type (frontend, backend, database, cloud, security), arrow styles (standard, dashed, curved), security groups, region boundaries, and the legend — use it as your structural reference when generating diagrams.