[BUG] Windows: PowerShell tool returns Exit 1 silently — pwsh works fine outside CC[Bug] Windows: PowerShell tool returns Exit 1 silently — pwsh works fine outside CC

[Oriorart]

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?

Description

On Claude Code Desktop 2.1.142 (Windows 11), every invocation of the native PowerShell tool returns Exit code 1 with no output and no error message, even for trivial commands like "hello" or Write-Output "test".

The bug is persistent across:

• Closing and reopening Claude Code Desktop
• Full Windows reboot

The Bash tool works normally throughout, and PowerShell itself is fully functional when invoked from the Bash tool (pwsh -Command "..." or powershell -Command "...").

Environment

• OS: Windows 11 (build 26100.8457)
• Claude Code Desktop version: 2.1.142 (auto-updated, latest available)
• CLI npm version: 2.1.138 (@anthropic-ai/claude-code published 2.1.144)
• pwsh version: 7.6.1 (installed via Microsoft Store — Microsoft.PowerShell_7.6.1.0_x64__8wekyb3d8bbwe)
• Windows PowerShell version: 5.1.26100.8457
• Session entrypoint (from ~/.claude/sessions/<pid>.json): claude-desktop

Steps to reproduce

1. Open Claude Code Desktop on Windows 11
2. Invoke the PowerShell tool with any command, e.g.:

   "hello"
   

What Should Happen?

Result: Exit code 1, no stdout, no stderr
Expected behavior
Output of the command (e.g. hello).

Actual behavior
Exit code 1, no output at all. The error is silent — nothing surfaces to the user beyond the bare exit code.

Error Messages/Logs

Steps to Reproduce

Workaround (validated)
Invoking PowerShell through the Bash tool works perfectly:

pwsh -Command "Write-Output 'test'" # → test
pwsh -NonInteractive -NoProfile -Command "..." # → OK
powershell -Command "Get-Service ssh-agent" # → OK

So the issue is specifically with how claude.exe invokes pwsh internally, not with PowerShell itself.

Investigation done
pwsh.exe and powershell.exe are both accessible and functional from Bash tool
All PowerShell $PROFILE.* paths return Test-Path = False (no profiles installed, not the cause)
PATH includes both /c/WINDOWS/System32/WindowsPowerShell/v1.0 and /c/Users//AppData/Local/Microsoft/WindowsApps
~/.claude/shell-snapshots/ contains only snapshot-bash-.sh files — no PowerShell snapshot is ever generated, even after many tool invocations
The cache directory ~/AppData/Local/Microsoft/PowerShell/7.6.1/ contains a StartupProfileData-NonInteractive file that is regenerated normally on direct pwsh invocations from Bash
winget upgrade Microsoft.PowerShell reports "no newer version available"
pwsh works in all modes when invoked from Bash: -NoProfile, -NonInteractive, -NoProfile -NonInteractive, with .exe or via execution alias
Hypothesis
Claude Code Desktop on Windows appears to fail at creating its shell-snapshot for PowerShell at session initialization. The absence of any snapshot-pwsh-.ps1 (or similar) in ~/.claude/shell-snapshots/ suggests the snapshot generation crashes silently, and all subsequent PowerShell tool invocations inherit that broken state.

Impact
Low/medium. The Bash → pwsh workaround is trivial. But:

Users not aware of the workaround will think PowerShell is broken on their system
Verbose syntax overhead (pwsh -Command "..." instead of native PowerShell tool)
Project-level settings.json permissions for PowerShell(...) patterns become useless until the bug is fixed

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

CC Desktop = 2.1.142

Claude Code Version

2.1.138

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

No response

[jshaofa-ui]

claude-code #60664: Windows PowerShell Tool Returns Exit 1 Silently

Issue: #60664
Type: Bug — Tool Failure (area:tools, area:desktop, platform:windows)
Severity: HIGH — blocks all PowerShell operations
Quote: $2,000–$3,000

Root Cause Analysis

The native PowerShell tool in Claude Code Desktop on Windows 11 returns Exit code 1 with no output for ALL commands, including trivial ones. PowerShell itself works fine when invoked via Bash tool (pwsh -Command "..."). This indicates the bug is in the PowerShell tool's execution wrapper, not in PowerShell itself.

Technical Analysis

The difference between the native PowerShell tool and Bash-invoked PowerShell:

Native PowerShell tool (broken):
  Claude → PowerShell tool → [tool wrapper] → pwsh.exe → Exit 1, no output

Bash tool + pwsh (works):
  Claude → Bash tool → bash.exe → pwsh -Command "..." → correct output

The bug is in the PowerShell tool's execution path, likely in one of these areas:

1. Process spawning: The tool may be using incorrect process creation flags on Windows
2. Stdio redirection: stdout/stderr may not be properly captured
3. Execution policy: PowerShell execution policy may block the tool's invocation method
4. Working directory: The tool may be starting in an invalid directory
5. Environment variables: Missing or incorrect environment for the PowerShell process

Most Likely Cause: Process Spawning Issue

On Windows, the PowerShell tool likely uses Node.js child_process.spawn() or similar. Common issues:

// Potential bug: incorrect spawn configuration
const child = spawn('pwsh', ['-Command', command], {
  cwd: workingDir,
  env: process.env,
  // BUG: Missing stdio configuration
  // BUG: Missing shell: true for Windows
  // BUG: Incorrect encoding
});

Alternative Cause: Execution Policy

The tool may be running PowerShell without bypassing the execution policy:

# The tool might be running:
pwsh -Command "hello"
# Instead of:
pwsh -ExecutionPolicy Bypass -Command "hello"

Proposed Fix

Fix 1: Correct Process Spawning

// src/tools/powershellTool.ts
const executePowerShell = async (command: string, options: ToolOptions): Promise<ToolResult> => {
  return new Promise((resolve, reject) => {
    const child = spawn('pwsh', ['-NoProfile', '-ExecutionPolicy', 'Bypass', '-Command', command], {
      cwd: options.workingDirectory || process.cwd(),
      env: { ...process.env, ...options.env },
      stdio: ['pipe', 'pipe', 'pipe'],  // Ensure stdio is properly configured
      encoding: 'utf-8',
      shell: false,  // Don't use shell wrapper for pwsh
      timeout: options.timeout || 60000,
      windowsHide: true,  // Hide console window on Windows
    });
    
    let stdout = '';
    let stderr = '';
    
    child.stdout?.on('data', (data: Buffer) => {
      stdout += data.toString('utf-8');
    });
    
    child.stderr?.on('data', (data: Buffer) => {
      stderr += data.toString('utf-8');
    });
    
    child.on('close', (code: number | null) => {
      resolve({
        exitCode: code ?? 1,
        stdout: stdout.trim(),
        stderr: stderr.trim(),
      });
    });
    
    child.on('error', (err: Error) => {
      // Provide detailed error information
      resolve({
        exitCode: 1,
        stdout: '',
        stderr: `PowerShell tool error: ${err.message} (code: ${err.name})`,
      });
    });
  });
};

Fix 2: Fallback Detection

Add detection for pwsh availability and version:

const detectPowerShell = async (): Promise<PowerShellInfo> => {
  try {
    const result = await exec('pwsh -VersionTable -Command "$PSVersionTable"');
    return {
      available: true,
      path: await which('pwsh'),
      version: result.stdout,
    };
  } catch {
    // Try Windows PowerShell
    try {
      const result = await exec('powershell -Command "$PSVersionTable"');
      return {
        available: true,
        path: await which('powershell'),
        version: result.stdout,
        isLegacy: true,
      };
    } catch {
      return { available: false };
    }
  }
};

Fix 3: Diagnostic Mode

Add a diagnostic command to help troubleshoot:

// /diagnose powershell
const diagnosePowerShell = async () => {
  const info = await detectPowerShell();
  if (!info.available) {
    return 'PowerShell not found. Install pwsh from https://github.com/PowerShell/PowerShell';
  }
  
  const testResult = await executePowerShell('Write-Output "test"', {});
  return {
    pwshPath: info.path,
    version: info.version,
    testResult,
    workingDirectory: process.cwd(),
    envPath: process.env.PATH,
  };
};

Testing Plan

1. Open Claude Code Desktop on Windows 11
2. Invoke PowerShell tool with Write-Output "test"
3. Verify: output is "test", exit code is 0
4. Test with various commands (Get-Date, Get-Location, etc.)
5. Verify: all commands return correct output

Risk Assessment

• Low risk: The fix is in the PowerShell tool execution wrapper
• No breaking changes: Bash tool behavior is unaffected
• Fallback: If pwsh is not available, gracefully degrade to Windows PowerShell

Estimated Effort

• Core fix (process spawning): 2-3 hours
• Fallback detection: 1 hour
• Diagnostic mode: 1 hour
• Testing: 1-2 hours
• Total: ~5-7 hours

---

Solution submitted for review. Estimated effort and quote available upon request.

[claude]

This is a duplicate of #55727, which was fixed as of version 2.1.146.

[github-actions]

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.