diff --git a/scripts/run_tests.sh b/scripts/run_tests.sh
index a54b7163d3f67..1027957ee85a4 100755
--- a/scripts/run_tests.sh
+++ b/scripts/run_tests.sh
@@ -39,9 +39,17 @@ REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
 
 # ── Activate venv ───────────────────────────────────────────────────────────
 VENV=""
-for candidate in "$REPO_ROOT/.venv" "$REPO_ROOT/venv" "$HOME/.hermes/hermes-agent/venv"; do
+PYTHON=""
+for candidate in "$REPO_ROOT/.venv" "$REPO_ROOT/venv" \
+  "$HOME/.hermes/hermes-agent/.venv" "$HOME/.hermes/hermes-agent/venv"; do
   if [ -f "$candidate/bin/activate" ]; then
     VENV="$candidate"
+    PYTHON="$candidate/bin/python"
+    break
+  fi
+  if [ -f "$candidate/Scripts/python.exe" ]; then
+    VENV="$candidate"
+    PYTHON="$candidate/Scripts/python.exe"
     break
   fi
 done
@@ -51,9 +59,6 @@ if [ -z "$VENV" ]; then
   exit 1
 fi
 
-PYTHON="$VENV/bin/python"
-
-
 # ── Live-gateway plugin (computed before we drop env) ───────────────────────
 EXTRA_PYTHONPATH=""
 EXTRA_PYTEST_PLUGINS=""
@@ -74,6 +79,8 @@ cd "$REPO_ROOT"
 exec env -i \
   PATH="$PATH" \
   HOME="$HOME" \
+  USERPROFILE="${USERPROFILE:-$HOME}" \
+  PYTHONUTF8=1 \
   TZ=UTC \
   LANG=C.UTF-8 \
   LC_ALL=C.UTF-8 \
diff --git a/tests/scripts/test_run_tests_windows_venv.py b/tests/scripts/test_run_tests_windows_venv.py
new file mode 100644
index 0000000000000..fdb34b6fae970
--- /dev/null
+++ b/tests/scripts/test_run_tests_windows_venv.py
@@ -0,0 +1,22 @@
+from pathlib import Path
+
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+RUNNER = REPO_ROOT / "scripts" / "run_tests.sh"
+
+
+def test_runner_supports_posix_and_windows_virtualenv_layouts():
+    script = RUNNER.read_text(encoding="utf-8")
+
+    assert 'if [ -f "$candidate/bin/activate" ]' in script
+    assert 'PYTHON="$candidate/bin/python"' in script
+    assert 'if [ -f "$candidate/Scripts/python.exe" ]' in script
+    assert 'PYTHON="$candidate/Scripts/python.exe"' in script
+    assert 'PYTHON="$VENV/bin/python"' not in script
+
+
+def test_runner_preserves_windows_home_and_utf8_in_clean_environment():
+    script = RUNNER.read_text(encoding="utf-8")
+
+    assert 'USERPROFILE="${USERPROFILE:-$HOME}"' in script
+    assert "PYTHONUTF8=1" in script
diff --git a/website/docs/user-guide/skills/bundled/autonomous-ai-agents/autonomous-ai-agents-hermes-agent.md b/website/docs/user-guide/skills/bundled/autonomous-ai-agents/autonomous-ai-agents-hermes-agent.md
index 2dde2ad9d1244..8ff01a3c20715 100644
--- a/website/docs/user-guide/skills/bundled/autonomous-ai-agents/autonomous-ai-agents-hermes-agent.md
+++ b/website/docs/user-guide/skills/bundled/autonomous-ai-agents/autonomous-ai-agents-hermes-agent.md
@@ -784,8 +784,9 @@ diagnostic recipe in `references/execute-code-sandbox-env-windows.md`.
 
 ### Testing / Contributing
 
-**`scripts/run_tests.sh` doesn't work as-is on Windows** — it looks for
-POSIX venv layouts (`.venv/bin/activate`). The Hermes-installed venv at
+**`scripts/run_tests.sh` supports native Windows venv layouts** — it probes
+both POSIX (`.venv/bin/python`) and Windows (`.venv/Scripts/python.exe`)
+interpreters. The Hermes-installed venv at
 `venv/Scripts/` has no pip or pytest either (stripped for install size).
 Workaround: install `pytest + pytest-xdist + pyyaml` into a system Python
 3.11 user site, then invoke pytest directly with `PYTHONPATH` set:
@@ -1004,14 +1005,15 @@ python -m pytest tests/tools/ -q            # Specific area
 - Run full suite before pushing any change
 - Use `-o 'addopts='` to clear any baked-in pytest flags
 
-**Windows contributors:** `scripts/run_tests.sh` currently looks for POSIX venvs (`.venv/bin/activate` / `venv/bin/activate`) and will error out on Windows where the layout is `venv/Scripts/activate` + `python.exe`. The Hermes-installed venv at `venv/Scripts/` also has no `pip` or `pytest` — it's stripped for end-user install size. Workaround: install pytest + pytest-xdist + pyyaml into a system Python 3.11 user site (`/c/Program Files/Python311/python -m pip install --user pytest pytest-xdist pyyaml`), then run tests directly:
+**Windows contributors:** `scripts/run_tests.sh` recognizes `venv/Scripts/python.exe` and preserves `USERPROFILE` plus UTF-8 mode in its clean environment. The Hermes-installed end-user venv may still omit `pip` or `pytest` to reduce install size; use a development venv with the test dependencies installed.
 
 ```bash
 export PYTHONPATH="$(pwd)"
 "/c/Program Files/Python311/python" -m pytest tests/tools/test_foo.py -v --tb=short -n 0
 ```
 
-Use `-n 0` (not `-n 4`) because `pyproject.toml`'s default `addopts` already includes `-n`, and the wrapper's CI-parity story doesn't apply off-POSIX.
+When invoking pytest directly, use `-n 0` (not `-n 4`) because
+`pyproject.toml`'s default `addopts` already includes `-n`.
 
 **Cross-platform test guards:** tests that use POSIX-only syscalls need a skip marker. Common ones already in the codebase:
 - Symlink creation → `@pytest.mark.skipif(sys.platform == "win32", reason="Symlinks require elevated privileges on Windows")` (see `tests/cron/test_cron_script.py`)