But they did deliver the internal notes, just told you to not look at them. Also the analogy doesn’t make a lot of sense to me since humans (or companies paying them) own the content they produce. Based on current precedent Anthropic doesn’t have any more rights to the LLM outputs produced by your inputs than you.
Whether that violates the ToS is another matter Anthropic is of course free to sue for damages or stop doing business with you.