[BUG] StatusLine not rendering in Windows Terminal despite successful script execution

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?

Environment

• OS: Windows 11 (Build 22631)
• Claude Code version: Latest (2.0.70 (Claude Code))
• Terminals tested:
• Git Bash standalone - WORKS
• VS Code integrated terminal (bash) - WORKS
• Windows Terminal with Git Bash profile - DOES NOT WORK
• Windows Terminal with PowerShell profile - DOES NOT WORK
• TERM: xterm-256color

Description

StatusLine commands execute successfully but output is never rendered when Claude Code runs inside Windows Terminal. The same configuration works perfectly in Git Bash standalone and VS Code's integrated terminal.

Configuration

~/.claude/settings.json:

{
  "statusLine": {
    "type": "command",
    "command": "powershell -NoProfile -ExecutionPolicy Bypass -File ~/.claude/statusline.ps1"
  }
}

~/.claude/statusline.ps1:

$e = [char]27
$j = $input | ConvertFrom-Json

$m = $j.model.display_name
$d = Split-Path $j.cwd -Leaf

$cu = $j.context_window.current_usage
$used = $cu.input_tokens + $cu.output_tokens + $cu.cache_creation_input_tokens + $cu.cache_read_input_tokens
$total = $j.context_window.context_window_size
$pct = [math]::Round(100 - ($used / $total * 100))

# Git info
$git = ''
try {
    $b = git -C $j.cwd branch --show-current 2>$null
    if ($b) {
        $dirty = ''
        $status = git -C $j.cwd status --porcelain 2>$null
        if ($status) { $dirty = '*' }
        $git = " ($b$dirty)"
    }
} catch {}

# Color based on percentage
$c = if ($pct -gt 50) { '32' } elseif ($pct -gt 30) { '33' } else { '31' }

$usedK = [math]::Round($used/1000)
$totalK = [math]::Round($total/1000)
[Console]::WriteLine("$e[35m$m$e[0m | $e[33m$d$e[36m$git$e[0m | $e[$c`m$pct% (${usedK}k/${totalK}k)$e[0m")

What Should Happen?

Expected behavior

StatusLine should display in Windows Terminal the same as it does in Git Bash standalone and VS Code integrated terminal.

Error Messages/Logs

2025-12-16 00:34:06 - Script started from: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
2025-12-16 00:34:06 - JSON parsed successfully
2025-12-16 00:34:06 - Output: Opus 4.5 | MyProject | 100% (0k/200k)
2025-12-16 00:34:10 - Script started from: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
2025-12-16 00:34:10 - JSON parsed successfully
2025-12-16 00:34:10 - Output: Opus 4.5 | MyProject | 57% (86k/200k)

Steps to Reproduce

1. Configure ~/.claude/settings.json with statusLine command (see Configuration)
2. Create ~/.claude/statusline.ps1 script (see Configuration)
3. Open Windows Terminal (Git Bash or PowerShell profile)
4. Run claude
5. Send any message
6. Observe: no statusline appears despite script executing successfully (proven by logs)

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.70 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

Proof that script executes successfully

Added debug logging to the script:

$logFile = "$env:USERPROFILE\.claude\statusline.log"
$timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
Add-Content $logFile "$timestamp - Script started from: $((Get-Process -Id $PID).Path)"
# ... after generating output ...
Add-Content $logFile "$timestamp - Output: $output"

Log output (from Windows Terminal session where statusline did NOT display):

2025-12-16 00:34:06 - Script started from: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
2025-12-16 00:34:06 - JSON parsed successfully
2025-12-16 00:34:06 - Output: Opus 4.5 | MyProject | 100% (0k/200k)
2025-12-16 00:34:10 - Script started from: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
2025-12-16 00:34:10 - JSON parsed successfully
2025-12-16 00:34:10 - Output: Opus 4.5 | MyProject | 57% (86k/200k)

What we tested

| Approach | Result |
|----------|--------|
| echo 'test' (simple cmd) | Works in Git Bash/VS Code, not in Windows Terminal |
| echo %USERNAME% (cmd variable) | Shows username - confirms cmd.exe context |
| powershell -Command "Write-Host 'test'" | Works in Git Bash/VS Code, not in Windows Terminal |
| PowerShell script with Write-Host | Script runs, no output in Windows Terminal |
| PowerShell script with stdout string | Script runs, no output in Windows Terminal |
| PowerShell script with [Console]::WriteLine() | Script runs, no output in Windows Terminal |
| $env:TERM | Already set to xterm-256color |

Root cause

Claude Code executes the statusline command via PowerShell correctly in all terminals (confirmed by logging). However, Claude Code fails to capture/render the output when running inside Windows Terminal, while it works in Git Bash standalone and VS Code integrated terminal.

This suggests the issue is in how Claude Code captures stdout from child processes when running inside Windows Terminal.

Related issues

• #5863 - macOS issue, closed due to inactivity (different platform, not applicable to Windows)
• #6526 - Closed incorrectly as duplicate of #5863

Neither issue addressed the Windows Terminal-specific problem.