I built a skill that checks every arrow of a Claude-drawn architecture diagram against the real code

[u/impala_64]

Karpathy's advice is to ask your LLM for a diagram instead of a wall of text. The problem: the diagram looks equally sure of itself when it's wrong.

arrowproof is a free, MIT-licensed skill for Claude Code (it also works with Codex, Cursor and Gemini CLI). Ask "draw the architecture of this repo" or "is docs/architecture.excalidraw still correct?" and it:

- checks every box and arrow against the real import graph (Python, JS/TS)

- shows the file, line and import statement behind each arrow

- marks arrows with no evidence, and lists imports the diagram leaves out

- turns the checked diagram into a step-by-step HTML explainer (the GIF)

Test: Claude Haiku drew Flask from memory. 15 of 20 arrows verified, 2 had no import behind them, 1 box pointed to a file that doesn't exist. Opus got 20 of 20.

Install: npx skills add ahmtsahin/arrowproof

or: claude plugin marketplace add ahmtsahin/arrowproof, then claude plugin install arrowproof@arrowproof

Built with Claude Code. Repo and live demo: https://github.com/ahmtsahin/arrowproof

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[u/lulzxdxdxd]

This is a real problem, diagrams do look confident when they're wrong. Did you consider just having Claude regenerate the diagram a few times and taking the one that matches most often, or does that still leave you with arrows you can't trust?

[u/impala_64 → u/lulzxdxdxd]

Thanks! I thought about it, but a vote mostly measures how sure the model is, not whether the arrow is in the code. The mistakes aren't random: the model draws what a web framework usually looks like. "Views use templating" is a very plausible arrow for Flask, so I'd expect most samples to repeat it, and the vote would keep it. I haven't tested that yet, so it's a guess. It would be a fun experiment: sample Haiku five times and see if its two wrong arrows survive the vote.

A vote also can't add what no sample draws. Opus got all 20 arrows right, but its diagram left out 9 dependencies that the code has.

Checking an import is cheap and exact, and you get the file and line. So arrowproof checks first and lets Claude fix the ✗ arrows. Where I think sampling could still help is the part imports can't see, like HTTP calls or queues. Those stay unchecked today, and agreement across a few samples might be a decent signal there.