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
- User describes their system architecture (components, connections, technologies)
- Generate the HTML file following the design system below
- Save with
write_fileto a.htmlfile (e.g.~/architecture-diagram.html) - 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:
Preview
After saving, suggest the user open it:
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
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:
- Draw an opaque background rect (
#0f172a) - 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"
- Security Groups: Dashed (
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:
- Header: Title with a pulsing dot indicator and subtitle
- Main SVG: The diagram contained within a rounded border card
- Summary Cards: A grid of three cards below the diagram for high-level details
- Footer: Minimal metadata
Info Card Pattern
Output Requirements
- Single File: One self-contained
.htmlfile - 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:
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.

