Environment

• Windows 11, Git for Windows (C:\Program Files\Git\bin\bash.exe)
• Hermes installed via the official install.sh path; terminal.backend: local
• Python 3.11 (Windows MSC build inside the hermes venv)

Reproduce

1. Install Git for Windows + Hermes on Windows (no WSL).
2. hermes chat, then run any terminal call — e.g. echo hello.
3. Result: {\"output\": \"\", \"exit_code\": 126} every time.

Browser tool also fails on Windows with WinError 193 (not a valid Win32 application) on every navigation.

Root Causes (3 independent bugs, same platform)

1. select.select on pipe fds is not supported on Windows.
tools/environments/base.py::_drain calls select.select([proc.stdout.fileno()], …), which raises OSError 10038 on Windows pipes. The except (ValueError, OSError): break swallows it and the drain thread exits immediately → stdout is never read. All terminal() calls return empty output, and _extract_cwd_from_output never sees the __HERMES_CWD__ marker so self.cwd is never synced.

2. get_temp_dir() returns /tmp.
LocalEnvironment.get_temp_dir falls back to /tmp. Python on Windows resolves that to C:\tmp (non-existent), so the snapshot/cwd files written by Git Bash at /tmp/hermes-* can never be read back by Python — every open(self._cwd_file) silently FileNotFoundErrors.

3. builtin cd rejects single-quoted Windows backslash paths → exit 126.
_wrap_command emits builtin cd 'C:\Users\…' || exit 126. Git Bash's cd builtin does not accept that form; it needs POSIX (/c/Users/…). This is the exact source of the 126.

(Bonus) Browser: tools/browser_tool.py launches npx/agent-browser (which are .cmd shims on Windows) via subprocess.Popen without shell=True, producing WinError 193.

Fix

All three terminal bugs are small, local patches:

tools/environments/base.py — branch _drain on Windows and do blocking proc.stdout.read(4096) instead of select. Subprocess pipe handles aren't propagated to grandchildren on Windows (Py 3.7+), so EOF arrives promptly.

tools/environments/local.py

• get_temp_dir(): on Windows, return tempfile.gettempdir().replace('\\', '/'). C:/Users/…/Temp is valid for both Python open() and Git Bash source.
• Add _win_to_posix_path (C:\foo → /c/foo) and _posix_to_win_path (/c/foo → C:/foo).
• Override LocalEnvironment._wrap_command to run cwd through _win_to_posix_path on Windows before building the script — fixes the builtin cd failure.
• In _run_bash, feed _posix_to_win_path(self.cwd) to subprocess.Popen(cwd=…) so CreateProcess still gets a Windows path even if self.cwd was updated from pwd -P output.

tools/browser_tool.py — on Windows, detect .cmd/.bat shims and invoke via shell=True (or prepend ['cmd','/c']).

I've tested these patches locally against my install and am happy to send a PR if useful.

Note

The install docs say "Requires WSL2 on Windows", but the code path actually targets Git Bash. Clarifying this (or actually supporting WSL2) would help.