diff --git a/libs/partners/anthropic/pyproject.toml b/libs/partners/anthropic/pyproject.toml
index f7a4356e138..ec7c9f1f4ac 100644
--- a/libs/partners/anthropic/pyproject.toml
+++ b/libs/partners/anthropic/pyproject.toml
@@ -8,7 +8,7 @@ license = { text = "MIT" }
 requires-python = ">=3.10"
 dependencies = [
     "anthropic<1,>=0.64.0",
-    "langchain-core<2.0.0,>=1.0.0",
+    "langchain-core<2.0.0,>=1.0.0a1",
     "pydantic<3.0.0,>=2.7.4",
 ]
 name = "langchain-anthropic"
diff --git a/libs/partners/openai/pyproject.toml b/libs/partners/openai/pyproject.toml
index fb7224a862d..66d50fe4491 100644
--- a/libs/partners/openai/pyproject.toml
+++ b/libs/partners/openai/pyproject.toml
@@ -7,7 +7,7 @@ authors = []
 license = { text = "MIT" }
 requires-python = ">=3.10"
 dependencies = [
-    "langchain-core<2.0.0,>=1.0.0",
+    "langchain-core<2.0.0,>=1.0.0a1",
     "openai<2.0.0,>=1.99.9",
     "tiktoken<1,>=0.7",
 ]