diff --git a/backend/pyproject.toml b/backend/pyproject.toml
index b0399fe..bb8fcf2 100644
--- a/backend/pyproject.toml
+++ b/backend/pyproject.toml
@@ -17,6 +17,7 @@ aiostream = "^0.6.2"
 llama-index = "0.10.63"
 cachetools = "^5.3.3"
 protobuf = "4.25.4"
+nltk = "^3.8.2"
 
 #arize-phoenix = "^4.12.0"
 openinference-instrumentation-llama-index="2.2.3"
@@ -32,6 +33,7 @@ llama-index-vector-stores-qdrant = "^0.2.14"
 chroma="^0.2.0"
 llama-index-vector-stores-chroma = "^0.1.10"
 llama-index-readers-json = "^0.1.5"
+llama-index-retrievers-bm25 = "^0.2.2"
 
 duckduckgo_search = "^6.2.6"