[BUG] Windows: Input field unresponsive after session start (stdin race condition)

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?

Titel:
Windows: Input field unresponsive after session start (stdin race
condition)

Body:
Environment:

• Claude Code: v2.1.31
• OS: Windows 11
• Terminals tested: VS Code Terminal, Windows Terminal

Behavior:

• claude --print "test" works (non-interactive mode)
• claude (interactive) starts, UI renders, but cannot type in

input field

• No keyboard input, no paste, no click works
• Must close terminal to exit
• Happens intermittently, not every time

Attempted fixes (none worked):

• Delayed start (1s sleep before claude)
• FORCE_COLOR=1, TERM=xterm-256color
• Disabling all custom hooks

Likely cause:
Race condition in Ink/React terminal initialization - UI renders
before stdin is ready.

What Should Happen?

When starting Claude Code with claude command, the interactive
input field should be immediately responsive and accept keyboard
input. Users should be able to type their prompt right after the
UI renders.

Error Messages/Logs

No error messages displayed. The UI renders correctly showing:     - Claude Code banner
  - Model info (Opus 4.5)                                          
  - Input prompt "❯ Try fix lint errors"
                                                                   
  But no keyboard input is accepted - no typing, no paste (Ctrl+V),
   no click response.
  The session must be forcefully closed (close terminal window).

Steps to Reproduce

1. Open Windows Terminal (or VS Code integrated terminal)
2. Run: claude
3. Wait for UI to render (banner, model info, input prompt

appears)

1. Try to type anything in the input field
2. Observe: No characters appear, keyboard input is ignored

Additional observations:

• Non-interactive mode works: claude --print "test" executes

correctly

• Problem occurs intermittently (not 100% of the time)
• Once stuck, no recovery possible - must close terminal
• Tested with clean config (no custom hooks) - problem persists
• Affects both Windows Terminal and VS Code Terminal

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

Claude Code v2.1.29

Claude Code Version

Claude Code v2.1.31

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_