Diagram Design Gains 2951 Stars in a Day—Claude’s Premium Skill Replaces Cheap Mermaid Charts

Design Principles

4 px grid alignment – all node coordinates are multiples of 4, eliminating skewed layouts.

Single‑focus accent color – only one highlight color is used for 1‑2 core nodes.

Three‑tier professional fonts – titles use Instrument Serif, body text uses Geist Sans, technical labels use Geist Mono.

Fixed visual density 4/10 – only essential business links are shown to reduce cognitive load.

Zero‑dependency Output

Diagram Design generates a self‑contained HTML file that embeds native SVG graphics. The file opens directly in a browser and can be exported as clean SVG or high‑resolution PNG without any build steps or external JavaScript.

Semantic‑first Logic (v2.3+)

Instead of “layout‑then‑function”, the tool first extracts business semantics (queues, data flows, permission boundaries, iteration loops) and then automatically selects the appropriate diagram type. The same semantic model can be rendered as an architecture diagram, a swim‑lane diagram, or a sequence diagram without re‑laying out nodes.

Installation

Claude Code

/plugin marketplace add cathrynlavery/diagram-design
/plugin install diagram-design@diagram-design
# Enable auto‑update in the Marketplace panel (third‑party plugins are disabled by default)

Codex

codex plugin marketplace add cathrynlavery/diagram-design
codex plugin add diagram-design@diagram-design
# Manual upgrade
codex plugin marketplace upgrade diagram-design

Pi

pi install https://github.com/cathrynlavery/diagram-design
/reload
pi update --extensions   # Pi has no automatic updates

Claude Cowork (enterprise)

Mirror the open‑source repository to a private GitHub, bind it in the organization marketplace, and enable automatic sync. PR merges trigger versioned updates.

Key Features

Automatic brand capture (≈60 s): fetches website colors and fonts, runs WCAG AA contrast checks, and generates a style guide.

27 native chart types covering architecture, flow, data modeling, planning, hierarchy, and analysis.

Natural‑language prompts generate diagrams without learning a DSL (e.g., 绘制我的前端+Cloudflare+Astro+CMS生产架构图).

Four adjustable parameters: format (html/svg/png), size (doc‑inline, slide‑16x9, social‑og, print‑a4), detail (faithful, balanced, simplified), audience (engineer, mixed, executive).

Export commands support static or animated HTML; animation respects prefers-reduced-motion for accessibility.

Chart Types (27)

Technical architecture : Architecture, Sequence, Layer Stack, Medallion, DP Integration, Legacy System, High‑Level Stack.

Process & decision : Flowchart, State Machine, Swimlane, Multi‑role Process, Loop (iteration flywheel).

Data modeling : Entity‑Relationship (ER), Security Matrix.

Planning & management : Timeline, Gantt, Quadrant, 2×2 Matrix, Org Chart.

Hierarchy : Tree, Nested, Pyramid.

Analysis & comparison : Venn, Radar, Bar, Line, Scatter.

Natural‑language Prompt Examples

绘制我的前端+Cloudflare+Astro+CMS生产架构图

做Q2项目优先级四象限图，区分高/低影响、高/低工作量

生成Bearer Token刷新401异常完整时序流程

Adjustable Parameters

Format : html (editable source), svg (vector), png (bitmap).

Size : doc-inline, slide-16x9, social-og, print-a4.

Detail : faithful (full nodes), balanced (moderate simplification), simplified (executive view).

Audience : engineer, mixed, executive.

Export Commands

# Pi platform
/export-diagram diagram.html
/export-diagram diagram.html --svg-only
/export-diagram diagram.html --png-only --scale=3   # 3× high‑resolution PNG

# Claude Code
/diagram-design:export diagram.html
/diagram-design:export diagram.html --svg-only

Animation Modes

reveal

– progressive appearance. step – step‑by‑step presentation. loop – continuous animation.

When the system prefers reduced motion, the animation is suppressed and a static frame is shown.

Brand Capture Workflow

Send onboard diagram-design to https://your‑company.com to the Agent.

Agent crawls the homepage, extracts background, text, accent colors, and the full font stack.

Agent validates contrast against WCAG AA; if failing, it proposes optimized colors.

Agent returns a style‑guide preview for confirmation.

Confirm with yes, apply it to write style-guide.md.

Custom edits can be made directly in skills/diagram-design/references/style-guide.md.

Common Pitfalls and Fixes

Installation : Third‑party plugins have auto‑update disabled; enable it manually in the Marketplace panel.

Pi updates : Pi does not auto‑update; run pi update --extensions after each release.

Detail limit : Diagrams with >24 complex nodes are auto‑simplified; use --detail=faithful to retain full detail.

Mermaid import : Complex Mermaid diagrams may lose details; check conversion logs and supplement manually.

draw.io import : External images are stripped; only business logic is kept.

Animated HTML export : Exporting PNG captures only the first frame; append ?motion=static to the URL to obtain a static image before export.

Comparison with Alternatives

Mermaid – low‑cost gray boxes, requires manual CSS for branding, limited import/export.

Figma – highly customizable but needs ~30 min of manual color tweaking and has a steep learning curve.

draw.io – office‑style appearance, manual theme configuration, no native Mermaid import.

Visio – outdated Windows‑only UI, limited theme options.

Diagram Design – magazine‑grade minimalism, one‑click brand capture, native Mermaid/draw.io import, HTML/SVG/PNG output, natural‑language interface.

Repository

https://github.com/cathrynlavery/diagram-design/