diff --git a/libs/core/pyproject.toml b/libs/core/pyproject.toml
index 7f50acb0ff9..05005e681af 100644
--- a/libs/core/pyproject.toml
+++ b/libs/core/pyproject.toml
@@ -91,6 +91,7 @@ addopts = "--snapshot-warn-unused --strict-markers --strict-config --durations=5
 markers = [ "requires: mark tests as requiring a specific library", "compile: mark placeholder test used to compile integration tests without running them",]
 asyncio_mode = "auto"
 filterwarnings = [ "ignore::langchain_core._api.beta_decorator.LangChainBetaWarning",]
+asyncio_default_fixture_loop_scope = "function"
 
 [tool.ruff.lint.pep8-naming]
 classmethod-decorators = [ "classmethod", "langchain_core.utils.pydantic.pre_init", "pydantic.field_validator", "pydantic.v1.root_validator",]