[BUG] command/chat history is not tied to session

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When I start two claude code instances in the same repository and they use different sessions
(eg., one is running for long, the other one is freshly created without resume),
then the up arrow key brings the history from the other session too.
It makes absolutely no sense to mix history between sessions. If there are different sessions, probably because they are used for different tasks, therefore the mixing of the history is really annoying.

What Should Happen?

When you push up-arrow, only go back in the history of the current session.

Error Messages/Logs

Steps to Reproduce

Open two claudes in the same directory, execute anything in one of them, press up arrow in the other.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_