Show HN: Vellum, the best diagram editor you'll ever use

The discussion centers on Vellum, a diagram editor the poster (JoshJamesAnthon) describes as combining whiteboard speed with polished architecture-diagram quality. Josh emphasized that Vellum stores diagrams as YAML, includes a "graph" section for diagram-as-code fans, and that he used Claude to assist with geometry tasks; he also made the source available on GitHub and linked to a marketing/about page. Commenters generally reacted positively to the tool itself, with a brief "Looks interesting" from elmopeto.

Opinion divides around whether diagrams should be drawn manually or generated by AI. User sajithdilshan said they rarely draw diagrams anymore, preferring to generate PlantUML or Mermaid via Claude. Josh replied that AI-generated diagrams are becoming the norm and Vellum supports that workflow, but he argued from his experience that AI diagrams are useful for quick comprehension and prototyping while being unsuitable for formal documentation or complex, node-heavy diagrams because they become messy. The exchange frames Vellum as accommodating both approaches while highlighting differing views on AI's appropriateness for precise, production-ready diagrams.