Windows: Exec tool returns empty output unless pty: true

Symptoms

• On Windows (10/11), exec tool calls with pty: false (or omitted) return empty output.
• Even commands that should have side effects appear to do nothing:
  • echo test > file.txt does not create file.txt
  • Write-Output test prints nothing
• The same commands work when pty: true.

Cause

This is a known regression affecting the Windows non-PTY execution path in some OpenClaw versions. Using pty: true routes execution through a different code path that continues to work.

Fix

1) Force PTY for all exec calls on Windows

When calling the exec tool, always include pty: true:

{ "command": "echo test", "pty": true }

2) If you need clean output, round-trip through a temp file

PTY mode can include ANSI escape sequences in the returned output. A simple workaround is to redirect output to a temp file and then read it back:

powershell -NoProfile -Command "echo test | Out-File -FilePath $env:TEMP\\exec.out -Encoding utf8; Get-Content $env:TEMP\\exec.out"

Verify

Run an exec call with pty: true:

echo test

You should see test in the tool output. If you use redirection, confirm the file actually exists and has content.

Related

• Enable Tools and Plugins (Advanced)
• OpenClaw on Native Windows: PATH, Scheduled Tasks, Node Host, and the Real Failure Modes
• OpenClaw Not Using Tools After the Update? Fix the ‘Only Chats, Doesn’t Act’ Problem
• OpenClaw docs: Exec tool
• GitHub: #19107, #20084