diff --git a/nemoguardrails/kb/kb.py b/nemoguardrails/kb/kb.py
index 685f8a9a0..bd440f842 100644
--- a/nemoguardrails/kb/kb.py
+++ b/nemoguardrails/kb/kb.py
@@ -167,6 +167,8 @@ async def build(self):
                 # We also save the file for future use
                 os.makedirs(CACHE_FOLDER, exist_ok=True)
                 basic_index = cast(BasicEmbeddingsIndex, self.index)
+                if not basic_index.embeddings_index:
+                    raise Exception("Couldn't create basic embeddings index")
                 basic_index.embeddings_index.save(cache_file)
 
                 # And, explicitly save the size as we need it when we reload
diff --git a/pyproject.toml b/pyproject.toml
index 6f841582d..8fa31661e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -157,6 +157,7 @@ pyright = "^1.1.405"
 include = [
   "nemoguardrails/rails/**",
   "nemoguardrails/actions/**",
+  "nemoguardrails/kb/**",
   "nemoguardrails/logging/**",
   "nemoguardrails/tracing/**",
   "tests/test_callbacks.py",