[simonether]

On Windows uvx kwork-mcp failed at import: the state directory, token store and write ledger relied on fcntl, POSIX modes and uids. This adds native Windows support without WSL. macOS and Linux behave as before.

All platform code goes through the new private_fs module, with the Win32 calls in windows.py (ctypes, no new dependencies):

• State directories are created by CreateDirectoryW with an owner-only protected DACL (current user and SYSTEM), so a directory never exists with its parent's permissions. An existing directory passes only if its owner is the user, SYSTEM or Administrators and its DACL, inheritable entries included, lets no one else in. OWNER RIGHTS counts as the owner, since os.mkdir(path, 0o700) grants it. Outside the profile, no one else may rename or re-permission the directories above the state directory, the counterpart of the POSIX check on shared-writable ancestors. A junction or symlink as the state directory, UNC and device paths, alternate data streams and reserved names are rejected.
• Token and lock files are checked by owner and DACL through their open handles, and the token also against the file that passed lstat. The SQLite ledger is checked by path before each connection, as on POSIX.
• Tokens are sealed with DPAPI for the current Windows user, with the account scope as entropy: another user cannot read or plant one, and a file copied to another account's name does not open. A record DPAPI cannot open (reset Windows password, moved profile) answers auth_expired, and a new login replaces it. On POSIX the record stays plain JSON under 0600, so existing stores need no migration.
• Locks use msvcrt.locking. The token is replaced by MoveFileExW with write-through, since Windows has no directory fsync. Renames and unlinks wait up to a second when an antivirus or the indexer holds a fresh file.
• State stays in ~/.local/state/kwork-mcp under the profile (%USERPROFILE%), not in AppData: packaged (MSIX) clients such as Claude Desktop see a per-app copy of AppData, so the server they start and the terminal would split the ledger and locks.
• login warns when run elevated (that may be another Windows account), points runs outside a console (Git Bash's mintty) to PowerShell, and prints cmd/PowerShell quoting, the Cursor config path and the Edit Config hint for Claude Desktop. Both entry points write UTF-8 to redirected stdout and stderr: in a pipe the cp1252 default crashed --help on the Russian text.

Two independent reviews (Win32 calls against the Microsoft docs; POSIX regressions, tests and docs) found no POSIX regressions; their findings are fixed here. CI gets mypy --platform win32 in the quality job and a Windows job (Python 3.12 and 3.14 on windows-2025) that runs the suite and the wheel smoke test. Coverage stays gated on Linux, where the Windows branches and windows.py are excluded. Tests of POSIX-only behavior (modes, umask, symlink walks, directory fsync) are skipped on Windows; tests/test_windows_support.py covers the Windows side with real ACL, junction, DPAPI and lock checks.

README, site and docs describe the Windows setup. Version 1.6.0.

Not checked yet: an interactive kwork-mcp login and a real client on a Windows machine, which CI cannot do without a terminal. To try the branch before release:

uvx --from https://github.com/simonether/kwork-mcp/archive/refs/heads/windows-support.zip kwork-mcp login