diagram-design: AI diagrams as deliverable static files
The GitHub repo cathrynlavery/diagram-design ranked second on the OpenGithubs weekly momentum chart dated 2026-09-14, gaining 7,208 stars that week; verified on 2026-09-15 it holds 39,807 stars, 2,528 forks, HTML as its main language, an MIT license, created 2026-04-16, last pushed 2026-09-10, with only 44 open issues. It is a diagram skill pack for Agent Skills compatible hosts including Claude Code, Codex, Factory Droid, Pi, GitHub Copilot, Kiro and OpenCode, and the official README claims 39 editorial diagram types, while the weekly chart blurb says 38, a discrepancy this piece resolves in favor of the README. Its output is self-contained HTML with inline SVG: no build step, no JavaScript, no external image dependency, openable offline by double-click, with each type shipping three static variants, minimal light, minimal dark and full-editorial. The design system is what defeats the AI look: a single accent color, one or two focal elements per diagram, 1px hairline borders, no shadows, a 10px border-radius ceiling, and every coordinate and gap divisible by four. It can redraw draw.io, Mermaid and Excalidraw sources into that system through four dials, format, size, detail and audience, emitting a fidelity ledger; it inherits components, relationships, grouping and direction but never source coordinates, palette or fonts. Its tagline is No Mermaid slop, yet it ships a Mermaid import path, a tension worth reading closely. The piece also covers brand onboarding that reads your homepage for palette and font stack, maps them to semantic tokens like paper, ink, muted and accent, checks WCAG AA contrast and emits a fidelity receipt; multi-client profile isolation; and the genuinely serious engineering: CI across three platforms, clipping detected by pixel diffing rather than geometry, plus gates for Sankey conservation, waterfall running totals, treemap area error and label collision, all built to catch diagrams that lie.