Note that I am talking about this product where the Claude session is running locally (remote LLM of course, but local Claude Code). They also have a "Claude Code on the Web" thing where the Claude instance is running on their server. In principle, they could be collecting and training on that data even if it never enters a session. But this product is running on your computer, and Anthropic only sees files pulled in by tool calls.
[*]"may" because depending on the execution, instead of directly uploading the screenshots, a (python) script may be created that does local processing and only upload derived output
In either case though, all the tool calls and output are part of the session and therefore Input. Even if it called a local OCR application to extract the info, it would probably then ingest that info to act on it (e.g. rename files). So the content is still being uploaded to Anthropic.
Note that you can opt-out of training in your profile settings. Now whether they continue to respect that into the future...
To be clear: I like what Anthropic is doing, they appear more trustworthy/serious than OpenAI, but Cowork will result in millions of unsuspecting users having complete folders full of data uploaded and persisted on servers, currently, owned by Anthropic.