I've had excellent luck using Claude Code to generate "mermaid diagrams" for me, and convert them to .png format headlessly using mmdc/puppeteer. Really helped me out with an engineering proposal I just finished. In past years I would have fumbled around with Visio forever and the result would have been worse.
I find Mermaid diagram rendering is quite ugly by default. I've gotten much better-looking results by asking it to just generate SVGs. As a bonus it can do animations too. e.g. see slide 3 here, which I first tried with Mermaid and then switched to SVG when I couldn't get the rendering to look good: https://talks.mk.gg/2026/atmosphereconf/
I now often have CC make technical/architecture diagrams with tikz, the results look much better than mermaid but still requires multiple iterations to fix bad arrows, bad layouts etc.
Diagrams are still far from solved. We need a good non-gameable diagrams benchmark.
I use Claude Code and Gemini and to LLM as a judge among the two to review each others result and generate a final mermiad diagram.
You can copy past the mermaid to excalidraw to visualize it.
do the same.
I just ask Claude code for mermaid to visualize any topic I'm discussing.
In a pinch, Claude is also quite good at ASCII art in my experience!
And yet people here insist that the height of an llm is not being above to draw a pelican or count letters in a word
Well, mermaid diagrams are "just" a list of nodes and their relations. You'd expect any llm capable of generating code to be able to generate them
Writing an SVG of a pelican riding a bicycle without being able to see the result and iterate based on that is incredibly difficult by comparison. I'm sure some humans could do it, but I sure can't. That's part of the beauty of it: it's very difficult to do but a toddler could judge the results
Writing an SVG of a diagram by hand would be somewhere on the middle ground. Or depending on the number of nodes might be even harder than the pelican. Layouting diagrams can get tricky very quickly. It's also one of Mermaid's biggest weaknesses
Just wait if they go public. Claude 5.4 fails the Pelican test stock sheds 20% of value pf news. Wall street wonders if the lack of front wheel means there is something seriously wrong with the stocks underlying value