diff --git a/checks.nix b/checks.nix
index c4577e9..3044d3e 100644
--- a/checks.nix
+++ b/checks.nix
@@ -12,7 +12,7 @@
     echo "PASS: All binaries present"
 
     echo "=== Checking version ==="
-    ${hermes-agent}/bin/hermes version 2>&1 | grep -q "Hermes Agent" || (echo "FAIL: version check"; exit 1)
+    ${hermes-agent}/bin/hermes --version 2>&1 | grep -q "Hermes Agent" || (echo "FAIL: version check"; exit 1)
     echo "PASS: Version check"
 
     echo "=== Checking key Python modules ==="
diff --git a/package.nix b/package.nix
index 9bdeaaa..3d6cf7e 100644
--- a/package.nix
+++ b/package.nix
@@ -223,6 +223,8 @@ pythonPackages.buildPythonApplication {
     firecrawl-py
     fal-client
     parallel-web
+    # tool_search BM25 stemming (upstream >=0.20.6, snowballstemmer==3.1.1)
+    snowballstemmer
     # TTS
     edge-tts
     faster-whisper