From 485aaf69b7f0930a5f6631752172d90a4a5575c6 Mon Sep 17 00:00:00 2001
From: Gille <4317663+helix4u@users.noreply.github.com>
Date: Thu, 3 Sep 2026 16:04:09 -0600
Subject: [PATCH] fix(local-runtime): find nvidia-smi in WSL driver path

---
 hermes_cli/local_runtime/hardware.py        |  8 +++++++-
 tests/hermes_cli/test_unified_pool_quirk.py | 16 ++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/hermes_cli/local_runtime/hardware.py b/hermes_cli/local_runtime/hardware.py
index 9dc51bc9af..0f8e2c1ce3 100644
--- a/hermes_cli/local_runtime/hardware.py
+++ b/hermes_cli/local_runtime/hardware.py
@@ -117,7 +117,7 @@ _smi_path_cache: "tuple[str | None] | None" = None
 
 def _nvidia_smi_path() -> str | None:
     """Absolute path to nvidia-smi, or None. PATH first (respects user overrides), then the
-    driver's known Windows install locations; on Linux/WSL the PATH lookup is the whole ladder."""
+    driver's known install locations on Windows and WSL."""
     global _smi_path_cache
     if _smi_path_cache is not None:
         return _smi_path_cache[0]
@@ -132,6 +132,12 @@ def _nvidia_smi_path() -> str | None:
             / "NVIDIA Corporation" / "NVSMI" / "nvidia-smi.exe",
         )
         found = next((str(c) for c in candidates if c.exists()), None)
+    elif found is None and sys.platform.startswith("linux"):
+        # The Windows display driver exposes nvidia-smi here inside WSL, but does not guarantee
+        # that the directory is present on PATH.
+        candidate = Path("/usr/lib/wsl/lib/nvidia-smi")
+        if candidate.exists():
+            found = str(candidate)
     _smi_path_cache = (found,)
     return found
 
diff --git a/tests/hermes_cli/test_unified_pool_quirk.py b/tests/hermes_cli/test_unified_pool_quirk.py
index 39c7c23ed7..881fc9a557 100644
--- a/tests/hermes_cli/test_unified_pool_quirk.py
+++ b/tests/hermes_cli/test_unified_pool_quirk.py
@@ -14,6 +14,10 @@ any discrete card."""
 
 from __future__ import annotations
 
+from pathlib import Path
+
+import pytest
+
 import hermes_cli.local_runtime.hardware as hw
 
 GIB = 1 << 30
@@ -185,6 +189,18 @@ def test_smi_resolver_caches_and_survives_empty_path(monkeypatch):
     assert len(calls) == 1
 
 
+@pytest.mark.linux_only
+def test_smi_resolver_uses_wsl_driver_path_when_path_is_empty(monkeypatch):
+    """WSL exposes nvidia-smi through the Windows driver directory even
+    when a service PATH cannot resolve it."""
+    wsl_smi = Path("/usr/lib/wsl/lib/nvidia-smi")
+    monkeypatch.setattr(hw, "_smi_path_cache", None)
+    monkeypatch.setattr(hw.shutil, "which", lambda name: None)
+    monkeypatch.setattr(hw.Path, "exists", lambda candidate: candidate == wsl_smi)
+
+    assert hw._nvidia_smi_path() == str(wsl_smi)
+
+
 # ── probe cache ──────────────────────────────────────────────