# Diagram Design

> Diagram Design is an agent skill: you describe a diagram (architecture, flowchart, sequence, quadrant and 42 other types) and the agent writes one HTML file with inline SVG in a fixed editorial style, optionally matched to your site's colours and fonts. It can redraw Mermaid, draw.io and Excalidraw files and export SVG or PNG (PNG needs Python Playwright). Output is not an editable diagram source. Needs a coding agent with a paid plan or key. MIT licence. Free add-on; it does not replace a paid product.

- Repository: https://github.com/cathrynlavery/diagram-design
- Official docs: https://github.com/cathrynlavery/diagram-design#readme
- Checked: 2026-10-18

## What it replaces
Nothing people pay for: a free tool, listed because people search for it.

## Facts, with sources

| Question | Status | Answer | Source | Checked |
|---|---|---|---|---|
| Runs on my machine? | Confirmed | Yes, the agent writes HTML files locally; only Google Fonts is loaded unless system fonts are chosen | https://github.com/cathrynlavery/diagram-design#readme | 2026-10-18 |
| Code licence | Confirmed | MIT | https://github.com/cathrynlavery/diagram-design/blob/main/LICENSE | 2026-10-18 |
| Model weights licence | Confirmed | No separate model weights | https://github.com/cathrynlavery/diagram-design#readme | 2026-10-18 |
| Commercial use | Confirmed | Yes, MIT allows commercial use | https://github.com/cathrynlavery/diagram-design/blob/main/LICENSE | 2026-10-18 |
| Paid services needed? | No | Needs an AI coding agent, which needs a paid plan or API key | https://github.com/cathrynlavery/diagram-design#install | 2026-10-18 |
| Hardware | Unknown | Not documented | none found | - |
| Operating systems | Confirmed | macOS and Linux commands documented; Windows covered in the cookbook (copies instead of symlinks without Developer Mode) | https://github.com/cathrynlavery/diagram-design#install | 2026-10-18 |
| Setup effort | Confirmed | Easy, one npx command or a plugin install; PNG export needs Playwright | https://github.com/cathrynlavery/diagram-design#install | 2026-10-18 |

GitHub: 59002 stars, 3795 forks, last push 2026-10-20, archived: no.
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Source: RepoQuarry (https://repoquarry.dev/projects/diagram-design). Data licence: CC BY 4.0. Quotes are from project documentation and belong to their authors.