pin pydantic api ref build
diff --git a/docs/api_reference/requirements.txt b/docs/api_reference/requirements.txt
index 568cafa427ddd8..d2a4e1cd7f017f 100644
--- a/docs/api_reference/requirements.txt
+++ b/docs/api_reference/requirements.txt
@@ -1,5 +1,6 @@
 -e libs/langchain
 -e libs/experimental
+pydantic<2
 autodoc_pydantic==1.8.0
 myst_parser
 nbsphinx==0.8.9
