[BUG] High baseline CPU/RAM on idle — v2.1.50 Windows 11

[M-YasirGhaffar]

Preflight Checklist

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

What's Wrong?

Two separate Claude Code CLI instances in plain CMD consuming 29% CPU and 1.4 GB RAM combined while essentially idle. Fresh PC boot, vanilla setup — no MCP servers, no plugins, no custom CLAUDE.md. Both terminals are sluggish: input lag, slow scrolling, delayed response streaming. Rest of the system runs fine.

Instance 1: Reading old messages, no active task
Instance 2: Resumed session, ~49k/200k context tokens, no active task

Process	CPU	RAM	Power Usage
Claude Code #1	14.5%	757 MB	Very High
Claude Code #2	14.5%	636 MB	Very High
Chrome (10 tabs)	1.2%	634 MB	Low

Environment:

• Version: 2.1.50
• OS: Windows 11
• Terminal: CMD
• Plan: Max5 subscription
• MCP servers: None
• Plugins: None
• No custom CLAUDE.md or rules

Related: #4953, #9711, #11122, #8968

Unlike those issues, this is not a gradual memory leak — it's high baseline consumption within minutes of a fresh boot on a completely vanilla setup.

What Should Happen?

A CLI tool should idle under 1-2% CPU, not 14.5% per instance. Memory should be in the 100-300 MB range, not 600-750 MB for a text-based terminal agent. Windows should not flag a command line tool as "Very High" power usage while it sits idle.

Error Messages/Logs

Steps to Reproduce

1. Fresh boot Windows 11 PC.
2. Open CMD, run claude. Read old messages — don't start any task.
3. Open second CMD, run claude, resume an older session (~49k tokens context).
4. Don't run any task in either instance.
5. Check Task Manager — observe 14.5% CPU, 600-750 MB RAM, and "Very High" power per process.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

No response

Claude Code Version

2.1.50

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

No response

[M-YasirGhaffar]

Update: Closed all sessions, restarted, and launched only a single Claude Code instance in CMD. Same issue persists — typing in the terminal has noticeable input lag, characters appear seconds after keystrokes. This rules out multiple instances being the cause. A single vanilla session with no MCP servers, no plugins, and no active task still makes the terminal sluggish and unresponsive.

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] High baseline CPU/RAM on idle — v2.1.50 Windows 11 #27548
2. [Bug] High CPU usage at idle/prompt state #22509
3. [Bug] High CPU usage during idle state #23085

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