diff --git a/wizard-work/spark/hermes_diag.py b/wizard-work/spark/hermes_diag.py
new file mode 100644
index 0000000..2399dc6
--- /dev/null
+++ b/wizard-work/spark/hermes_diag.py
@@ -0,0 +1,22 @@
+#!/usr/bin/env python3
+"""Hermes environment diagnostic - verifies key paths and permissions."""
+import json
+import os
+from pathlib import Path
+
+diag = {
+    "profile": os.environ.get("SPARK_PROFILE", "spark"),
+    "home": str(Path.home()),
+    "cwd": str(Path.cwd()),
+    "scratch": "/root/.hermes/profiles/spark/cache/scratch",
+    "forge_token": ("<set>" if os.environ.get("FORGE_TOKEN") else "<unset>"),
+    "checks": {}
+}
+
+for name, p in [("home", Path.home()), ("scratch", Path(diag["scratch"]))]:
+    diag["checks"][name] = {
+        "exists": p.exists(),
+        "writable": os.access(p, os.W_OK) if p.exists() else False
+    }
+
+print(json.dumps(diag, indent=2))
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