Claude Visualizer + Lucid AI/MCP + diagrams.net/Excalidraw + Napkin AI + GPT Images accelerate AI diagram workflows

Excalidraw MCP VS Code server enables secure editable AI diagrams (Transformer demos, Claude Sonnet polishes); VLM UML struggles highlight reasoning gaps; May 2026 arXiv 'Diagram of Thought' adds LLM dynamic mental maps. New: Draw2Think (May 2026) Propose-Draw-Verify loop with GeoGebra offloads reasoning to constraint-checked canvas, improves VLM geometry accuracy 16.4%, parallels human drawing-as-thinking. Ongoing: Lucid voice-to-BPMN, Claude Code Mermaid onboarding, GPT 'think before draws'; trust/polish issues persist, cog data limited.