[BUG] Claude Code usage increases immediately upon launch without user input

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?

I have recently observed a consistent issue where Claude Code's usage begins to climb 1-3% as soon as the instance is launched, even if no prompts are sent.

I have reproduced this behavior multiple times; the usage increases during idle periods immediately following startup

What Should Happen?

Simply launching the instance shouldn't effect the usage

Error Messages/Logs

Steps to Reproduce

Check usage at https://claude.ai/settings/usage
Launch CC in terminal
Check again and it will 1-2% higher

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.3

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_