For the user's name it's intentional; they template it into the system prompt with no option to disable it.
For 99% of users, the model knows it's in the /home/joesmith/whatever repo and `git log` shows the last change was by `[email protected]` - trying to keep the user's identity secret from the model would be nigh-impossible so I think anthropic gave up on even trying.
But that still doesn't answer the question of why Claude passes the info to web sites. What if it finds your banking information in a personal file and uses it to achieve its goal, which is not different technically?
> `git log` shows the last change was by `[email protected]`
GitHub offers noreply email addresses
You can absolutely remove an email from the context, at the model API it's tokens in tokens out.
I use the name "Human" for that but it overrides with its knowledge of my name from other stuff quite regularly.