diff --git a/python/langsmith/run_helpers.py b/python/langsmith/run_helpers.py
index 7bc64b444..70852ea17 100644
--- a/python/langsmith/run_helpers.py
+++ b/python/langsmith/run_helpers.py
@@ -17,11 +17,15 @@
     Callable,
     Dict,
     Generator,
+    Generic,
     List,
     Mapping,
     Optional,
+    Protocol,
     TypedDict,
+    TypeVar,
     cast,
+    runtime_checkable,
 )
 
 from langsmith import client, run_trees, utils
@@ -223,6 +227,20 @@ def _setup_run(
     return response_container
 
 
+R = TypeVar("R", covariant=True)
+
+
+@runtime_checkable
+class SupportsLangsmithExtra(Protocol, Generic[R]):
+    def __call__(
+        self,
+        *args: Any,
+        langsmith_extra: Optional[Dict[str, Any]] = None,
+        **kwargs: Any,
+    ) -> R:
+        ...
+
+
 def traceable(
     run_type: str = "chain",
     *,
@@ -233,7 +251,7 @@ def traceable(
     client: Optional[client.Client] = None,
     extra: Optional[Dict] = None,
     reduce_fn: Optional[Callable] = None,
-) -> Callable:
+) -> Callable[[Callable[..., R]], SupportsLangsmithExtra[R]]:
     """Decorator for creating or adding a run to a run tree.
 
     Args:
diff --git a/python/pyproject.toml b/python/pyproject.toml
index 294a55db2..923b26902 100644
--- a/python/pyproject.toml
+++ b/python/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "langsmith"
-version = "0.0.77"
+version = "0.0.78"
 description = "Client library to connect to the LangSmith LLM Tracing and Evaluation Platform."
 authors = ["LangChain <support@langchain.dev>"]
 license = "MIT"
diff --git a/python/tests/unit_tests/test_client.py b/python/tests/unit_tests/test_client.py
index 39079c208..8e03b6ece 100644
--- a/python/tests/unit_tests/test_client.py
+++ b/python/tests/unit_tests/test_client.py
@@ -106,7 +106,7 @@ def test_upload_csv(mock_session_cls: mock.Mock) -> None:
     assert dataset.description == "Test dataset"
 
 
-def test_async_methods():
+def test_async_methods() -> None:
     """For every method defined on the Client, if there is a
 
     corresponding async method, then the async method args should be a
@@ -140,7 +140,7 @@ def test_async_methods():
         )
 
 
-def test_get_api_key():
+def test_get_api_key() -> None:
     assert _get_api_key("provided_api_key") == "provided_api_key"
     assert _get_api_key("'provided_api_key'") == "provided_api_key"
     assert _get_api_key('"_provided_api_key"') == "_provided_api_key"
@@ -155,7 +155,7 @@ def test_get_api_key():
     assert _get_api_key(" ") is None
 
 
-def test_get_api_url():
+def test_get_api_url() -> None:
     assert _get_api_url("http://provided.url", "api_key") == "http://provided.url"
 
     with patch.dict(os.environ, {"LANGCHAIN_ENDPOINT": "http://env.url"}):
@@ -174,7 +174,7 @@ def test_get_api_url():
         _get_api_url(" ", "api_key")
 
 
-def test_create_run_unicode():
+def test_create_run_unicode() -> None:
     client = Client(api_url="http://localhost:1984", api_key="123")
     inputs = {
         "foo": "これは私の友達です",
@@ -194,7 +194,7 @@ def test_create_run_unicode():
 
 
 @pytest.mark.parametrize("source_type", ["api", "model"])
-def test_create_feedback_string_source_type(source_type: str):
+def test_create_feedback_string_source_type(source_type: str) -> None:
     client = Client(api_url="http://localhost:1984", api_key="123")
     session = mock.Mock()
     request_object = mock.Mock()
@@ -215,7 +215,7 @@ def test_create_feedback_string_source_type(source_type: str):
         )
 
 
-def test_pydantic_serialize():
+def test_pydantic_serialize() -> None:
     """Test that pydantic objects can be serialized."""
     test_uuid = uuid.uuid4()
     test_time = datetime.now()