diff --git a/tests/test_windows_subprocess_no_window_flags.py b/tests/test_windows_subprocess_no_window_flags.py
index 3c99bdb5055..8ae181f654b 100644
--- a/tests/test_windows_subprocess_no_window_flags.py
+++ b/tests/test_windows_subprocess_no_window_flags.py
@@ -941,3 +941,154 @@ def test_lsp_install_go_hides_console_window(monkeypatch, tmp_path):
     assert kwargs["creationflags"] == _CREATE_NO_WINDOW
     assert kwargs["stdin"] == subprocess.DEVNULL
     assert kwargs["capture_output"] is True
+
+
+# ── #67690 env probes, lazy installs, platform.win32_ver() (@m4r13y) ───────
+#
+# Windowless processes (pythonw gateway + kanban workers) flashed consoles
+# from three more spawn families: tools/env_probe._run's interpreter/pip
+# probes, tools/lazy_deps' uv→pip→ensurepip install ladder, and CPython
+# 3.11/3.12's platform.win32_ver() which shells out `cmd /c ver` with
+# shell=True and no CREATE_NO_WINDOW. All are hide-only (creationflags);
+# win32_ver is neutralized by stubbing platform._syscmd_ver so the
+# documented ValueError fallback reads sys.getwindowsversion() instead.
+
+
+def test_env_probe_run_hides_console_window(monkeypatch):
+    from tools import env_probe
+
+    captured = []
+
+    def fake_run(cmd, **kwargs):
+        captured.append((cmd, kwargs))
+        return _Completed(stdout="", returncode=0)
+
+    monkeypatch.setattr(env_probe, "windows_hide_flags", lambda: _CREATE_NO_WINDOW)
+    monkeypatch.setattr(env_probe.subprocess, "run", fake_run)
+
+    rc, out, err = env_probe._run(["python3", "--version"], timeout=1.0)
+
+    assert rc == 0
+    assert len(captured) == 1, captured
+    cmd, kwargs = captured[0]
+    assert cmd == ["python3", "--version"]
+    assert kwargs["creationflags"] == _CREATE_NO_WINDOW
+    # The temp-file capture contract (#67964) must survive: stdout/stderr are
+    # file objects (not PIPE) so a lingering grandchild can't wedge the probe.
+    assert kwargs["stdout"] is not None and kwargs["stdout"] != subprocess.PIPE
+    assert kwargs["stderr"] is not None and kwargs["stderr"] != subprocess.PIPE
+    assert kwargs["stdin"] == subprocess.DEVNULL
+
+
+def test_lazy_deps_uv_install_hides_console_window(monkeypatch):
+    from tools import lazy_deps
+
+    captured = []
+
+    def fake_run(cmd, **kwargs):
+        captured.append((cmd, kwargs))
+        return _Completed(stdout="installed", returncode=0)
+
+    monkeypatch.delenv(lazy_deps._LAZY_TARGET_ENV, raising=False)
+    monkeypatch.setattr(lazy_deps, "windows_hide_flags", lambda: _CREATE_NO_WINDOW)
+    monkeypatch.setattr(lazy_deps.subprocess, "run", fake_run)
+    monkeypatch.setattr(lazy_deps.shutil, "which", lambda name: "/usr/bin/uv" if name == "uv" else None)
+
+    res = lazy_deps._venv_pip_install(("left-pad",))
+
+    assert res.success
+    spawns = _spawns(captured, "pip", "install", "left-pad")
+    assert len(spawns) == 1, captured
+    cmd, kwargs = spawns[0]
+    assert cmd[:3] == ["/usr/bin/uv", "pip", "install"]
+    assert kwargs["creationflags"] == _CREATE_NO_WINDOW
+    assert kwargs["stdin"] == subprocess.DEVNULL
+
+
+def test_lazy_deps_pip_probe_and_install_hide_console_window(monkeypatch):
+    """No uv: the pip --version probe and the pip install fallback both hide."""
+    from tools import lazy_deps
+
+    captured = []
+
+    def fake_run(cmd, **kwargs):
+        captured.append((cmd, kwargs))
+        return _Completed(stdout="pip 25.0", returncode=0)
+
+    monkeypatch.delenv(lazy_deps._LAZY_TARGET_ENV, raising=False)
+    monkeypatch.setattr(lazy_deps, "windows_hide_flags", lambda: _CREATE_NO_WINDOW)
+    monkeypatch.setattr(lazy_deps.subprocess, "run", fake_run)
+    monkeypatch.setattr(lazy_deps.shutil, "which", lambda name: None)
+
+    res = lazy_deps._venv_pip_install(("left-pad",))
+
+    assert res.success
+    probes = _spawns(captured, "-m", "pip", "--version")
+    installs = _spawns(captured, "-m", "pip", "install", "left-pad")
+    assert len(probes) == 1 and len(installs) == 1, captured
+    for _cmd, kwargs in probes + installs:
+        assert kwargs["creationflags"] == _CREATE_NO_WINDOW
+        assert kwargs["stdin"] == subprocess.DEVNULL
+
+
+def test_lazy_deps_ensurepip_hides_console_window(monkeypatch):
+    """Failed pip probe: the ensurepip bootstrap spawn hides too."""
+    from tools import lazy_deps
+
+    captured = []
+
+    def fake_run(cmd, **kwargs):
+        captured.append((cmd, kwargs))
+        if "--version" in cmd:
+            return _Completed(stdout="", returncode=1)  # probe fails → ensurepip
+        return _Completed(stdout="ok", returncode=0)
+
+    monkeypatch.delenv(lazy_deps._LAZY_TARGET_ENV, raising=False)
+    monkeypatch.setattr(lazy_deps, "windows_hide_flags", lambda: _CREATE_NO_WINDOW)
+    monkeypatch.setattr(lazy_deps.subprocess, "run", fake_run)
+    monkeypatch.setattr(lazy_deps.shutil, "which", lambda name: None)
+
+    res = lazy_deps._venv_pip_install(("left-pad",))
+
+    assert res.success
+    bootstraps = _spawns(captured, "-m", "ensurepip", "--upgrade")
+    assert len(bootstraps) == 1, captured
+    assert bootstraps[0][1]["creationflags"] == _CREATE_NO_WINDOW
+
+
+def test_suppress_platform_ver_console_posix_noop(monkeypatch):
+    """On POSIX the helper must do nothing at all and never raise."""
+    import platform
+
+    from hermes_cli import _subprocess_compat
+
+    monkeypatch.setattr(_subprocess_compat, "IS_WINDOWS", False)
+    original = platform._syscmd_ver
+
+    _subprocess_compat.suppress_platform_ver_console()
+
+    assert platform._syscmd_ver is original
+    # win32_ver stays functional (returns empty fields off Windows).
+    assert platform.win32_ver() == ("", "", "", "")
+
+
+def test_suppress_platform_ver_console_stubs_syscmd_ver(monkeypatch):
+    """Simulated Windows: _syscmd_ver is replaced by an in-process echo stub
+    so win32_ver() takes its ValueError fallback instead of `cmd /c ver`."""
+    import platform
+
+    from hermes_cli import _subprocess_compat
+
+    monkeypatch.setattr(_subprocess_compat, "IS_WINDOWS", True)
+    # Register the original with monkeypatch so it gets restored after.
+    monkeypatch.setattr(platform, "_syscmd_ver", platform._syscmd_ver)
+
+    _subprocess_compat.suppress_platform_ver_console()
+
+    # The stub echoes its inputs — win32_ver() treats the unparseable value
+    # as the documented ValueError path and falls back to
+    # sys.getwindowsversion().platform_version (no subprocess, no window).
+    assert platform._syscmd_ver("s", "r", "v") == ("s", "r", "v")
+    # Idempotent + never raises on repeat calls.
+    _subprocess_compat.suppress_platform_ver_console()
+    assert platform._syscmd_ver() == ("", "", "")
diff --git a/tools/env_probe.py b/tools/env_probe.py
index 95427cc1c9a..6e28a51cfd2 100644
--- a/tools/env_probe.py
+++ b/tools/env_probe.py
@@ -38,6 +38,8 @@ import tempfile
 import threading
 from typing import Optional
 
+from hermes_cli._subprocess_compat import windows_hide_flags
+
 logger = logging.getLogger(__name__)
 
 # Module-level cache.  The probe result is deterministic for the
@@ -105,6 +107,11 @@ def _run(cmd: list[str], timeout: float = 3.0) -> tuple[int, str, str]:
                     timeout=timeout,
                     check=False,
                     stdin=subprocess.DEVNULL,
+                    # CREATE_NO_WINDOW (0 on POSIX): the probe runs in
+                    # windowless processes (pythonw gateway / kanban workers)
+                    # where a console child would otherwise flash a visible
+                    # window per probe — ~5 flashes at every worker startup.
+                    creationflags=windows_hide_flags(),
                 )
             except subprocess.TimeoutExpired:
                 return -1, "", "timeout"