diff --git a/packages/rag/default.nix b/packages/rag/default.nix
index 423c53a..925a8cb 100644
--- a/packages/rag/default.nix
+++ b/packages/rag/default.nix
@@ -34,7 +34,9 @@ writers.writePython3Bin "rag"
 
 
     def embed(texts):
-        resp = client.embeddings.create(model=EMBED_MODEL, input=texts)
+        # encoding_format is explicit: llama.cpp rejects a null value, and
+        # LiteLLM forwards an unset one as JSON null.
+        resp = client.embeddings.create(model=EMBED_MODEL, input=texts, encoding_format="float")
         return [d.embedding for d in resp.data]