diff --git a/semantica/vector_store/methods.py b/semantica/vector_store/methods.py
index d74d763b..5a558b27 100644
--- a/semantica/vector_store/methods.py
+++ b/semantica/vector_store/methods.py
@@ -297,7 +297,11 @@ def create_index(
     config = vector_store_config.get_all()
     backend = config.get("default_backend", "faiss")
     dimension = config.get("dimension", 768)
-    indexer = VectorIndexer(backend=backend, dimension=dimension, **config)
+    # backend/dimension are already passed explicitly; drop them from the
+    # forwarded config so VectorIndexer(..., **remaining_config) doesn't
+    # receive duplicate keyword arguments.
+    remaining_config = {k: v for k, v in config.items() if k not in ("default_backend", "dimension")}
+    indexer = VectorIndexer(backend=backend, dimension=dimension, **remaining_config)
     return indexer.create_index(vectors, ids, **options)
 
 
diff --git a/tests/vector_store/test_vector_store.py b/tests/vector_store/test_vector_store.py
index 219f88c2..80ff3e59 100644
--- a/tests/vector_store/test_vector_store.py
+++ b/tests/vector_store/test_vector_store.py
@@ -243,5 +243,19 @@ class TestVectorStore(unittest.TestCase):
             shutil.rmtree(tmpdir, ignore_errors=True)
 
 
+class TestCreateIndexFunction(unittest.TestCase):
+    """create_index() forwards vector_store_config's defaults into VectorIndexer,
+    which already receives backend/dimension as explicit args. Regression for the
+    'got multiple values for keyword argument dimension' crash on the default
+    (unmocked) config, hit by e.g. `semantica embed index`."""
+
+    def test_create_index_with_default_config(self):
+        from semantica.vector_store.methods import create_index
+
+        vectors = [np.array([0.1, 0.2, 0.3]), np.array([0.4, 0.5, 0.6])]
+        index = create_index(vectors, ids=["a", "b"])
+        self.assertIsNotNone(index)
+
+
 if __name__ == '__main__':
     unittest.main()