He did the right thing. The very idea of Claude copying an existing project to answer one of my prompts or a whole project in Claude Code is a nightmare scenario.

I have all but given up using the multiple trillion weight models in favor of smaller open weight models that have hopefully abstracted away copyrightable details. Right now deepseek-v4-flash-0731 seems usually perfect for my needs.

I saw Cees de Groot post about LLM vibe coded projects containing all sorts of licensed material, and I think he is correct.

Perhaps another good reason to just use the AGPL for new projects? I decided to use the AGPL for may latest fun project https://github.com/mark-watson/racket-coding-agent (personal AI coding harness written for my own use in Racket Scheme). Everything I do is open source or open content books, so I am happy to have everything I do to be used by humans and also for AI training, however: it is scary to by mistake be in the position of not acknowledging other work when appropriate.