Diagram Design is an open-source agent skill that produces editorial-quality diagrams as self-contained HTML and SVG instead of generic rounded-box output.
It supports dozens of technical and business diagram types, matches your brand by reading your website, and works in Claude Code, Codex, GitHub Copilot, Factory Droid, Pi and other Agent Skills-compatible hosts.
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50+ diagram types including architecture, sequence, ER, state machine, dependency graph, UML class and database schema
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Self-contained HTML + SVG output with no build step, JavaScript or external image dependency
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Brand matching that reads your website to pick colors and type
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Optional accessible motion and semantic system patterns
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Redraws existing Mermaid, draw.io or Excalidraw sources at a chosen format and detail level
Free
Diagram Design is free and open source under the MIT license; it installs as an agent skill or Claude Code plugin and runs inside your existing coding agent.
Best for
Developers and writers who want polished architecture and documentation diagrams generated directly by their coding agent.
Not ideal for
Teams that need collaborative, interactive diagram editing or diagrams verified against source code.
A tasteful, low-friction way to get publication-ready diagrams out of any skills-compatible coding agent.
Version 2.5.10 added ten more layout grammars such as Sankey, Wardley map, UML class and database schema, and the repository appeared on GitHub Trending in October 2026 with more than 43,000 stars.
As of
Is Diagram Design free?+
Yes - Diagram Design is Free. Diagram Design is free and open source under the MIT license; it installs as an agent skill or Claude Code plugin and runs inside your existing coding agent.
Is Diagram Design open source?+
Yes - Diagram Design is open source. Diagram Design is free and open source under the MIT license; it installs as an agent skill or Claude Code plugin and runs inside your existing coding agent.
Who is Diagram Design best for?+
Developers and writers who want polished architecture and documentation diagrams generated directly by their coding agent.
Who is Diagram Design not ideal for?+
Teams that need collaborative, interactive diagram editing or diagrams verified against source code.
What are the best Diagram Design alternatives?+
The closest Diagram Design alternatives on ai.dosa.dev are Pieces for Developers, agenttrace, Vibe Kanban - all listed under Developer Productivity & Workflow.
Who makes Diagram Design?+
Diagram Design is developed by Cathryn Lavery (LittleMight). It is listed in the Developer Productivity & Workflow category on ai.dosa.dev.
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