diff --git a/libs/core/langchain_core/document_loaders/langsmith.py b/libs/core/langchain_core/document_loaders/langsmith.py
index 57cac1347c5..33446350b07 100644
--- a/libs/core/langchain_core/document_loaders/langsmith.py
+++ b/libs/core/langchain_core/document_loaders/langsmith.py
@@ -125,7 +125,7 @@ class LangSmithLoader(BaseLoader):
             yield Document(content_str, metadata=metadata)
 
 
-def _stringify(x: Union[str, dict]) -> str:
+def _stringify(x: Union[str, dict[str, Any]]) -> str:
     if isinstance(x, str):
         return x
     try:
diff --git a/libs/core/langchain_core/messages/utils.py b/libs/core/langchain_core/messages/utils.py
index 21815d7626c..cb3e18d18b9 100644
--- a/libs/core/langchain_core/messages/utils.py
+++ b/libs/core/langchain_core/messages/utils.py
@@ -202,13 +202,17 @@ def message_chunk_to_message(chunk: BaseMessageChunk) -> BaseMessage:
 
 
 MessageLikeRepresentation = Union[
-    BaseMessage, list[str], tuple[str, str], str, dict[str, Any]
+    BaseMessage,
+    list[str],
+    tuple[str, Union[str, list[Union[str, dict[str, Any]]]]],
+    str,
+    dict[str, Any],
 ]
 
 
 def _create_message_from_message_type(
     message_type: str,
-    content: str,
+    content: Union[str, list[Union[str, dict[str, Any]]]],
     name: Optional[str] = None,
     tool_call_id: Optional[str] = None,
     tool_calls: Optional[list[dict[str, Any]]] = None,
@@ -218,13 +222,13 @@ def _create_message_from_message_type(
     """Create a message from a message type and content string.
 
     Args:
-        message_type: (str) the type of the message (e.g., "human", "ai", etc.).
-        content: (str) the content string.
-        name: (str) the name of the message. Default is None.
-        tool_call_id: (str) the tool call id. Default is None.
-        tool_calls: (list[dict[str, Any]]) the tool calls. Default is None.
-        id: (str) the id of the message. Default is None.
-        additional_kwargs: (dict[str, Any]) additional keyword arguments.
+        message_type: the type of the message (e.g., "human", "ai", etc.).
+        content: the content string.
+        name: the name of the message. Default is None.
+        tool_call_id: the tool call id. Default is None.
+        tool_calls: the tool calls. Default is None.
+        id: the id of the message. Default is None.
+        **additional_kwargs: additional keyword arguments.
 
     Returns:
         a message of the appropriate type.
@@ -1004,12 +1008,13 @@ def convert_to_openai_messages(
 
     oai_messages: list = []
 
-    if is_single := isinstance(messages, (BaseMessage, dict, str)):
-        messages = [messages]
+    messages_ = (
+        [messages]
+        if (is_single := isinstance(messages, (BaseMessage, dict, str, tuple)))
+        else messages
+    )
 
-    messages = convert_to_messages(messages)
-
-    for i, message in enumerate(messages):
+    for i, message in enumerate(convert_to_messages(messages_)):
         oai_msg: dict = {"role": _get_message_openai_role(message)}
         tool_messages: list = []
         content: Union[str, list[dict]]
diff --git a/libs/core/langchain_core/output_parsers/openai_functions.py b/libs/core/langchain_core/output_parsers/openai_functions.py
index 708eb5bd81b..a748c773eb2 100644
--- a/libs/core/langchain_core/output_parsers/openai_functions.py
+++ b/libs/core/langchain_core/output_parsers/openai_functions.py
@@ -225,7 +225,7 @@ class PydanticOutputFunctionsParser(OutputFunctionsParser):
 
     @model_validator(mode="before")
     @classmethod
-    def validate_schema(cls, values: dict) -> Any:
+    def validate_schema(cls, values: dict[str, Any]) -> Any:
         """Validate the pydantic schema.
 
         Args:
diff --git a/libs/core/langchain_core/prompts/chat.py b/libs/core/langchain_core/prompts/chat.py
index 924762457f3..2e9c62347c5 100644
--- a/libs/core/langchain_core/prompts/chat.py
+++ b/libs/core/langchain_core/prompts/chat.py
@@ -3,9 +3,9 @@
 from __future__ import annotations
 
 from abc import ABC, abstractmethod
+from collections.abc import Sequence
 from pathlib import Path
 from typing import (
-    TYPE_CHECKING,
     Annotated,
     Any,
     Optional,
@@ -51,9 +51,6 @@ from langchain_core.prompts.string import (
 from langchain_core.utils import get_colored_text
 from langchain_core.utils.interactive_env import is_interactive_env
 
-if TYPE_CHECKING:
-    from collections.abc import Sequence
-
 
 class MessagesPlaceholder(BaseMessagePromptTemplate):
     """Prompt template that assumes variable is already list of messages.
@@ -772,7 +769,7 @@ MessageLikeRepresentation = Union[
     MessageLike,
     tuple[
         Union[str, type],
-        Union[str, list[dict], list[object]],
+        Union[str, Sequence[dict], Sequence[object]],
     ],
     str,
     dict[str, Any],
@@ -1435,11 +1432,13 @@ def _convert_to_message_template(
                     f" Got: {message}"
                 )
                 raise ValueError(msg)
-            message = (message["role"], message["content"])
-        if len(message) != 2:
-            msg = f"Expected 2-tuple of (role, template), got {message}"
-            raise ValueError(msg)
-        message_type_str, template = message
+            message_type_str = message["role"]
+            template = message["content"]
+        else:
+            if len(message) != 2:
+                msg = f"Expected 2-tuple of (role, template), got {message}"
+                raise ValueError(msg)
+            message_type_str, template = message
         if isinstance(message_type_str, str):
             message_ = _create_template_from_message_type(
                 message_type_str, template, template_format=template_format
diff --git a/libs/core/langchain_core/tracers/evaluation.py b/libs/core/langchain_core/tracers/evaluation.py
index c7447ad4d81..71049ef00e8 100644
--- a/libs/core/langchain_core/tracers/evaluation.py
+++ b/libs/core/langchain_core/tracers/evaluation.py
@@ -100,7 +100,7 @@ class EvaluatorCallbackHandler(BaseTracer):
             )
         else:
             self.executor = None
-        self.futures: weakref.WeakSet[Future] = weakref.WeakSet()
+        self.futures: weakref.WeakSet[Future[None]] = weakref.WeakSet()
         self.skip_unfinished = skip_unfinished
         self.project_name = project_name
         self.logged_eval_results: dict[tuple[str, str], list[EvaluationResult]] = {}
diff --git a/libs/core/tests/unit_tests/example_selectors/test_base.py b/libs/core/tests/unit_tests/example_selectors/test_base.py
index 54793627987..8f94d005b32 100644
--- a/libs/core/tests/unit_tests/example_selectors/test_base.py
+++ b/libs/core/tests/unit_tests/example_selectors/test_base.py
@@ -10,7 +10,7 @@ class DummyExampleSelector(BaseExampleSelector):
     def add_example(self, example: dict[str, str]) -> None:
         self.example = example
 
-    def select_examples(self, input_variables: dict[str, str]) -> list[dict]:
+    def select_examples(self, input_variables: dict[str, str]) -> list[dict[str, str]]:
         return [input_variables]
 
 
diff --git a/libs/core/tests/unit_tests/fake/callbacks.py b/libs/core/tests/unit_tests/fake/callbacks.py
index b8ec1778b42..2defad94699 100644
--- a/libs/core/tests/unit_tests/fake/callbacks.py
+++ b/libs/core/tests/unit_tests/fake/callbacks.py
@@ -276,7 +276,9 @@ class FakeCallbackHandler(BaseCallbackHandler, BaseFakeCallbackHandlerMixin):
         self.on_retriever_error_common()
 
     # Overriding since BaseModel has __deepcopy__ method as well
-    def __deepcopy__(self, memo: dict) -> "FakeCallbackHandler":  # type: ignore[override]
+    def __deepcopy__(
+        self, memo: Union[dict[int, Any], None] = None
+    ) -> "FakeCallbackHandler":
         return self
 
 
@@ -426,5 +428,7 @@ class FakeAsyncCallbackHandler(AsyncCallbackHandler, BaseFakeCallbackHandlerMixi
         self.on_text_common()
 
     # Overriding since BaseModel has __deepcopy__ method as well
-    def __deepcopy__(self, memo: dict) -> "FakeAsyncCallbackHandler":  # type: ignore[override]
+    def __deepcopy__(
+        self, memo: Union[dict[int, Any], None] = None
+    ) -> "FakeAsyncCallbackHandler":
         return self
diff --git a/libs/core/tests/unit_tests/language_models/chat_models/test_base.py b/libs/core/tests/unit_tests/language_models/chat_models/test_base.py
index 41b197cd8c2..7f30c1eadbb 100644
--- a/libs/core/tests/unit_tests/language_models/chat_models/test_base.py
+++ b/libs/core/tests/unit_tests/language_models/chat_models/test_base.py
@@ -41,7 +41,7 @@ if TYPE_CHECKING:
 
 
 @pytest.fixture
-def messages() -> list:
+def messages() -> list[BaseMessage]:
     return [
         SystemMessage(content="You are a test user."),
         HumanMessage(content="Hello, I am a test user."),
@@ -49,14 +49,14 @@ def messages() -> list:
 
 
 @pytest.fixture
-def messages_2() -> list:
+def messages_2() -> list[BaseMessage]:
     return [
         SystemMessage(content="You are a test user."),
         HumanMessage(content="Hello, I not a test user."),
     ]
 
 
-def test_batch_size(messages: list, messages_2: list) -> None:
+def test_batch_size(messages: list[BaseMessage], messages_2: list[BaseMessage]) -> None:
     # The base endpoint doesn't support native batching,
     # so we expect batch_size to always be 1
     llm = FakeListChatModel(responses=[str(i) for i in range(100)])
@@ -80,7 +80,9 @@ def test_batch_size(messages: list, messages_2: list) -> None:
         assert (cb.traced_runs[0].extra or {}).get("batch_size") == 1
 
 
-async def test_async_batch_size(messages: list, messages_2: list) -> None:
+async def test_async_batch_size(
+    messages: list[BaseMessage], messages_2: list[BaseMessage]
+) -> None:
     llm = FakeListChatModel(responses=[str(i) for i in range(100)])
     # The base endpoint doesn't support native batching,
     # so we expect batch_size to always be 1
@@ -262,7 +264,7 @@ async def test_astream_implementation_uses_astream() -> None:
 class FakeTracer(BaseTracer):
     def __init__(self) -> None:
         super().__init__()
-        self.traced_run_ids: list = []
+        self.traced_run_ids: list[uuid.UUID] = []
 
     def _persist_run(self, run: Run) -> None:
         """Persist a run."""
@@ -415,7 +417,7 @@ async def test_disable_streaming_no_streaming_model_async(
 class FakeChatModelStartTracer(FakeTracer):
     def __init__(self) -> None:
         super().__init__()
-        self.messages: list = []
+        self.messages: list[list[list[BaseMessage]]] = []
 
     def on_chat_model_start(self, *args: Any, **kwargs: Any) -> Run:
         _, messages = args
diff --git a/libs/core/tests/unit_tests/messages/test_utils.py b/libs/core/tests/unit_tests/messages/test_utils.py
index 0898341dda8..a5ec976ba4b 100644
--- a/libs/core/tests/unit_tests/messages/test_utils.py
+++ b/libs/core/tests/unit_tests/messages/test_utils.py
@@ -17,6 +17,7 @@ from langchain_core.messages import (
     ToolMessage,
 )
 from langchain_core.messages.utils import (
+    MessageLikeRepresentation,
     convert_to_messages,
     convert_to_openai_messages,
     count_tokens_approximately,
@@ -153,7 +154,7 @@ def test_merge_messages_tool_messages() -> None:
         {"include_names": ["blah", "blur"], "exclude_types": [SystemMessage]},
     ],
 )
-def test_filter_message(filters: dict) -> None:
+def test_filter_message(filters: dict[str, Any]) -> None:
     messages = [
         SystemMessage("foo", name="blah", id="1"),
         HumanMessage("bar", name="blur", id="2"),
@@ -673,7 +674,7 @@ class FakeTokenCountingModel(FakeChatModel):
 
 
 def test_convert_to_messages() -> None:
-    message_like: list = [
+    message_like: list[MessageLikeRepresentation] = [
         # BaseMessage
         SystemMessage("1"),
         SystemMessage("1.1", additional_kwargs={"__openai_role__": "developer"}),
@@ -1179,7 +1180,7 @@ def test_convert_to_openai_messages_mixed_content_types() -> None:
 
 
 def test_convert_to_openai_messages_developer() -> None:
-    messages: list = [
+    messages: list[MessageLikeRepresentation] = [
         SystemMessage("a", additional_kwargs={"__openai_role__": "developer"}),
         {"role": "developer", "content": "a"},
     ]
diff --git a/libs/core/tests/unit_tests/output_parsers/test_openai_tools.py b/libs/core/tests/unit_tests/output_parsers/test_openai_tools.py
index 3fbb65c63b0..9c8c341657f 100644
--- a/libs/core/tests/unit_tests/output_parsers/test_openai_tools.py
+++ b/libs/core/tests/unit_tests/output_parsers/test_openai_tools.py
@@ -17,7 +17,7 @@ from langchain_core.output_parsers.openai_tools import (
 )
 from langchain_core.outputs import ChatGeneration
 
-STREAMED_MESSAGES: list = [
+STREAMED_MESSAGES = [
     AIMessageChunk(content=""),
     AIMessageChunk(
         content="",
@@ -331,7 +331,7 @@ for message in STREAMED_MESSAGES:
         STREAMED_MESSAGES_WITH_TOOL_CALLS.append(message)
 
 
-EXPECTED_STREAMED_JSON = [
+EXPECTED_STREAMED_JSON: list[dict[str, Any]] = [
     {},
     {"names": ["suz"]},
     {"names": ["suzy"]},
@@ -392,7 +392,7 @@ def test_partial_json_output_parser(*, use_tool_calls: bool) -> None:
     chain = input_iter | JsonOutputToolsParser()
 
     actual = list(chain.stream(None))
-    expected: list = [[]] + [
+    expected: list[list[dict[str, Any]]] = [[]] + [
         [{"type": "NameCollector", "args": chunk}] for chunk in EXPECTED_STREAMED_JSON
     ]
     assert actual == expected
@@ -404,7 +404,7 @@ async def test_partial_json_output_parser_async(*, use_tool_calls: bool) -> None
     chain = input_iter | JsonOutputToolsParser()
 
     actual = [p async for p in chain.astream(None)]
-    expected: list = [[]] + [
+    expected: list[list[dict[str, Any]]] = [[]] + [
         [{"type": "NameCollector", "args": chunk}] for chunk in EXPECTED_STREAMED_JSON
     ]
     assert actual == expected
@@ -416,7 +416,7 @@ def test_partial_json_output_parser_return_id(*, use_tool_calls: bool) -> None:
     chain = input_iter | JsonOutputToolsParser(return_id=True)
 
     actual = list(chain.stream(None))
-    expected: list = [[]] + [
+    expected: list[list[dict[str, Any]]] = [[]] + [
         [
             {
                 "type": "NameCollector",
@@ -435,7 +435,9 @@ def test_partial_json_output_key_parser(*, use_tool_calls: bool) -> None:
     chain = input_iter | JsonOutputKeyToolsParser(key_name="NameCollector")
 
     actual = list(chain.stream(None))
-    expected: list = [[]] + [[chunk] for chunk in EXPECTED_STREAMED_JSON]
+    expected: list[list[dict[str, Any]]] = [[]] + [
+        [chunk] for chunk in EXPECTED_STREAMED_JSON
+    ]
     assert actual == expected
 
 
@@ -446,7 +448,9 @@ async def test_partial_json_output_parser_key_async(*, use_tool_calls: bool) ->
     chain = input_iter | JsonOutputKeyToolsParser(key_name="NameCollector")
 
     actual = [p async for p in chain.astream(None)]
-    expected: list = [[]] + [[chunk] for chunk in EXPECTED_STREAMED_JSON]
+    expected: list[list[dict[str, Any]]] = [[]] + [
+        [chunk] for chunk in EXPECTED_STREAMED_JSON
+    ]
     assert actual == expected
 
 
diff --git a/libs/core/tests/unit_tests/output_parsers/test_pydantic_parser.py b/libs/core/tests/unit_tests/output_parsers/test_pydantic_parser.py
index 0486878749a..7dfe651622e 100644
--- a/libs/core/tests/unit_tests/output_parsers/test_pydantic_parser.py
+++ b/libs/core/tests/unit_tests/output_parsers/test_pydantic_parser.py
@@ -141,9 +141,7 @@ DEF_EXPECTED_RESULT = TestModel(
 
 def test_pydantic_output_parser() -> None:
     """Test PydanticOutputParser."""
-    pydantic_parser: PydanticOutputParser = PydanticOutputParser(
-        pydantic_object=TestModel
-    )
+    pydantic_parser = PydanticOutputParser(pydantic_object=TestModel)
 
     result = pydantic_parser.parse(DEF_RESULT)
     assert result == DEF_EXPECTED_RESULT
@@ -152,9 +150,7 @@ def test_pydantic_output_parser() -> None:
 
 def test_pydantic_output_parser_fail() -> None:
     """Test PydanticOutputParser where completion result fails schema validation."""
-    pydantic_parser: PydanticOutputParser = PydanticOutputParser(
-        pydantic_object=TestModel
-    )
+    pydantic_parser = PydanticOutputParser(pydantic_object=TestModel)
 
     with pytest.raises(
         OutputParserException, match="Failed to parse TestModel from completion"
diff --git a/libs/core/tests/unit_tests/outputs/test_chat_generation.py b/libs/core/tests/unit_tests/outputs/test_chat_generation.py
index c409a76f0de..d9e8ca9f0b8 100644
--- a/libs/core/tests/unit_tests/outputs/test_chat_generation.py
+++ b/libs/core/tests/unit_tests/outputs/test_chat_generation.py
@@ -1,4 +1,4 @@
-from typing import Union
+from typing import Any, Union
 
 import pytest
 
@@ -19,14 +19,14 @@ from langchain_core.outputs import ChatGeneration
         ],
     ],
 )
-def test_msg_with_text(content: Union[str, list]) -> None:
+def test_msg_with_text(content: Union[str, list[Union[str, dict[str, Any]]]]) -> None:
     expected = "foo"
     actual = ChatGeneration(message=AIMessage(content=content)).text
     assert actual == expected
 
 
 @pytest.mark.parametrize("content", [[], [{"tool_use": {}, "type": "tool_use"}]])
-def test_msg_no_text(content: Union[str, list]) -> None:
+def test_msg_no_text(content: Union[str, list[Union[str, dict[str, Any]]]]) -> None:
     expected = ""
     actual = ChatGeneration(message=AIMessage(content=content)).text
     assert actual == expected
diff --git a/libs/core/tests/unit_tests/prompts/test_chat.py b/libs/core/tests/unit_tests/prompts/test_chat.py
index f873deb0877..2703cfdc550 100644
--- a/libs/core/tests/unit_tests/prompts/test_chat.py
+++ b/libs/core/tests/unit_tests/prompts/test_chat.py
@@ -1,7 +1,7 @@
 import re
 import warnings
 from pathlib import Path
-from typing import Any, Union, cast
+from typing import Any, Union
 
 import pytest
 from packaging import version
@@ -121,11 +121,10 @@ def test_create_system_message_prompt_template_from_template_partial() -> None:
     History:
     {history}
     """
-    json_prompt_instructions: dict = {}
     graph_analyst_template = SystemMessagePromptTemplate.from_template(
         template=graph_creator_content,
         input_variables=["history"],
-        partial_variables={"instructions": json_prompt_instructions},
+        partial_variables={"instructions": {}},
     )
     assert graph_analyst_template.format(history="history") == SystemMessage(
         content="\n    Your instructions are:\n    {}\n    History:\n    history\n    "
@@ -973,46 +972,43 @@ def test_chat_tmpl_serdes(snapshot: SnapshotAssertion) -> None:
             ("system", "You are an AI assistant named {name}."),
             ("system", [{"text": "You are an AI assistant named {name}."}]),
             SystemMessagePromptTemplate.from_template("you are {foo}"),
-            cast(
-                "tuple",
-                (
-                    "human",
-                    [
-                        "hello",
-                        {"text": "What's in this image?"},
-                        {"type": "text", "text": "What's in this image?"},
-                        {
-                            "type": "text",
-                            "text": "What's in this image?",
-                            "cache_control": {"type": "{foo}"},
+            (
+                "human",
+                [
+                    "hello",
+                    {"text": "What's in this image?"},
+                    {"type": "text", "text": "What's in this image?"},
+                    {
+                        "type": "text",
+                        "text": "What's in this image?",
+                        "cache_control": {"type": "{foo}"},
+                    },
+                    {
+                        "type": "image_url",
+                        "image_url": "data:image/jpeg;base64,{my_image}",
+                    },
+                    {
+                        "type": "image_url",
+                        "image_url": {"url": "data:image/jpeg;base64,{my_image}"},
+                    },
+                    {"type": "image_url", "image_url": "{my_other_image}"},
+                    {
+                        "type": "image_url",
+                        "image_url": {
+                            "url": "{my_other_image}",
+                            "detail": "medium",
                         },
-                        {
-                            "type": "image_url",
-                            "image_url": "data:image/jpeg;base64,{my_image}",
-                        },
-                        {
-                            "type": "image_url",
-                            "image_url": {"url": "data:image/jpeg;base64,{my_image}"},
-                        },
-                        {"type": "image_url", "image_url": "{my_other_image}"},
-                        {
-                            "type": "image_url",
-                            "image_url": {
-                                "url": "{my_other_image}",
-                                "detail": "medium",
-                            },
-                        },
-                        {
-                            "type": "image_url",
-                            "image_url": {"url": "https://www.langchain.com/image.png"},
-                        },
-                        {
-                            "type": "image_url",
-                            "image_url": {"url": "data:image/jpeg;base64,foobar"},
-                        },
-                        {"image_url": {"url": "data:image/jpeg;base64,foobar"}},
-                    ],
-                ),
+                    },
+                    {
+                        "type": "image_url",
+                        "image_url": {"url": "https://www.langchain.com/image.png"},
+                    },
+                    {
+                        "type": "image_url",
+                        "image_url": {"url": "data:image/jpeg;base64,foobar"},
+                    },
+                    {"image_url": {"url": "data:image/jpeg;base64,foobar"}},
+                ],
             ),
             ("placeholder", "{chat_history}"),
             MessagesPlaceholder("more_history", optional=False),
@@ -1179,7 +1175,7 @@ def test_chat_prompt_template_data_prompt_from_message(
     cache_control_placeholder: str,
     source_data_placeholder: str,
 ) -> None:
-    prompt: dict = {
+    prompt: dict[str, Any] = {
         "type": "image",
         "source_type": "base64",
         "data": f"{source_data_placeholder}",
diff --git a/libs/core/tests/unit_tests/prompts/test_few_shot.py b/libs/core/tests/unit_tests/prompts/test_few_shot.py
index 3e768cf380b..dcae9d08812 100644
--- a/libs/core/tests/unit_tests/prompts/test_few_shot.py
+++ b/libs/core/tests/unit_tests/prompts/test_few_shot.py
@@ -385,7 +385,7 @@ class AsIsSelector(BaseExampleSelector):
         raise NotImplementedError
 
     @override
-    def select_examples(self, input_variables: dict[str, str]) -> list[dict]:
+    def select_examples(self, input_variables: dict[str, str]) -> list[dict[str, str]]:
         return list(self.examples)
 
 
@@ -480,11 +480,13 @@ class AsyncAsIsSelector(BaseExampleSelector):
     def add_example(self, example: dict[str, str]) -> Any:
         raise NotImplementedError
 
-    def select_examples(self, input_variables: dict[str, str]) -> list[dict]:
+    def select_examples(self, input_variables: dict[str, str]) -> list[dict[str, str]]:
         raise NotImplementedError
 
     @override
-    async def aselect_examples(self, input_variables: dict[str, str]) -> list[dict]:
+    async def aselect_examples(
+        self, input_variables: dict[str, str]
+    ) -> list[dict[str, str]]:
         return list(self.examples)
 
 
diff --git a/libs/core/tests/unit_tests/prompts/test_loading.py b/libs/core/tests/unit_tests/prompts/test_loading.py
index 76d75314775..ac0d7510332 100644
--- a/libs/core/tests/unit_tests/prompts/test_loading.py
+++ b/libs/core/tests/unit_tests/prompts/test_loading.py
@@ -15,7 +15,7 @@ EXAMPLE_DIR = (Path(__file__).parent.parent / "examples").absolute()
 
 
 @contextmanager
-def change_directory(dir_path: Path) -> Iterator:
+def change_directory(dir_path: Path) -> Iterator[None]:
     """Change the working directory to the right folder."""
     origin = Path().absolute()
     try:
diff --git a/libs/core/tests/unit_tests/prompts/test_prompt.py b/libs/core/tests/unit_tests/prompts/test_prompt.py
index e092eb66581..be281f9a74b 100644
--- a/libs/core/tests/unit_tests/prompts/test_prompt.py
+++ b/libs/core/tests/unit_tests/prompts/test_prompt.py
@@ -265,7 +265,7 @@ def test_prompt_from_template_with_partial_variables() -> None:
 def test_prompt_missing_input_variables() -> None:
     """Test error is raised when input variables are not provided."""
     template = "This is a {foo} test."
-    input_variables: list = []
+    input_variables: list[str] = []
     with pytest.raises(
         ValueError,
         match=re.escape("check for mismatched or missing input parameters from []"),
@@ -509,7 +509,7 @@ Your variable again: {{ foo }}
 def test_prompt_jinja2_missing_input_variables() -> None:
     """Test error is raised when input variables are not provided."""
     template = "This is a {{ foo }} test."
-    input_variables: list = []
+    input_variables: list[str] = []
     with pytest.warns(UserWarning, match="Missing variables: {'foo'}"):
         PromptTemplate(
             input_variables=input_variables,
diff --git a/libs/core/tests/unit_tests/prompts/test_structured.py b/libs/core/tests/unit_tests/prompts/test_structured.py
index 0b74b37cc6f..112c24b753b 100644
--- a/libs/core/tests/unit_tests/prompts/test_structured.py
+++ b/libs/core/tests/unit_tests/prompts/test_structured.py
@@ -14,11 +14,15 @@ from langchain_core.utils.pydantic import is_basemodel_subclass
 
 
 def _fake_runnable(
-    _: Any, *, schema: Union[dict, type[BaseModel]], value: Any = 42, **_kwargs: Any
-) -> Union[BaseModel, dict]:
+    _: Any,
+    *,
+    schema: Union[dict[str, Any], type[BaseModel]],
+    value: Any = 42,
+    **_kwargs: Any,
+) -> Union[BaseModel, dict[str, Any]]:
     if isclass(schema) and is_basemodel_subclass(schema):
         return schema(name="yo", value=value)
-    params = cast("dict", schema)["parameters"]
+    params = cast("dict[str, Any]", schema)["parameters"]
     return {k: 1 if k != "value" else value for k, v in params.items()}
 
 
diff --git a/libs/core/tests/unit_tests/runnables/test_concurrency.py b/libs/core/tests/unit_tests/runnables/test_concurrency.py
index 24d4fad5d23..a18ab172723 100644
--- a/libs/core/tests/unit_tests/runnables/test_concurrency.py
+++ b/libs/core/tests/unit_tests/runnables/test_concurrency.py
@@ -6,8 +6,7 @@ from typing import Any
 
 import pytest
 
-from langchain_core.runnables import RunnableConfig, RunnableLambda
-from langchain_core.runnables.base import Runnable
+from langchain_core.runnables import Runnable, RunnableConfig, RunnableLambda
 
 
 @pytest.mark.asyncio
@@ -97,7 +96,7 @@ def test_batch_concurrency() -> None:
 
         return f"Completed {x}"
 
-    runnable: Runnable = RunnableLambda(tracked_function)
+    runnable = RunnableLambda(tracked_function)
     num_tasks = 10
     max_concurrency = 3
 
@@ -129,7 +128,7 @@ def test_batch_as_completed_concurrency() -> None:
 
         return f"Completed {x}"
 
-    runnable: Runnable = RunnableLambda(tracked_function)
+    runnable = RunnableLambda(tracked_function)
     num_tasks = 10
     max_concurrency = 3
 
diff --git a/libs/core/tests/unit_tests/runnables/test_config.py b/libs/core/tests/unit_tests/runnables/test_config.py
index dc7f1c5d0ca..5897879d90a 100644
--- a/libs/core/tests/unit_tests/runnables/test_config.py
+++ b/libs/core/tests/unit_tests/runnables/test_config.py
@@ -26,7 +26,7 @@ from langchain_core.tracers.stdout import ConsoleCallbackHandler
 
 def test_ensure_config() -> None:
     run_id = str(uuid.uuid4())
-    arg: dict = {
+    arg: dict[str, Any] = {
         "something": "else",
         "metadata": {"foo": "bar"},
         "configurable": {"baz": "qux"},
@@ -147,7 +147,7 @@ async def test_merge_config_callbacks() -> None:
 def test_config_arbitrary_keys() -> None:
     base: RunnablePassthrough[Any] = RunnablePassthrough()
     bound = base.with_config(my_custom_key="my custom value")
-    config = cast("RunnableBinding", bound).config
+    config = cast("RunnableBinding[Any, Any]", bound).config
 
     assert config.get("my_custom_key") == "my custom value"
 
diff --git a/libs/core/tests/unit_tests/runnables/test_context.py b/libs/core/tests/unit_tests/runnables/test_context.py
index b638ac78f57..0756eeaf285 100644
--- a/libs/core/tests/unit_tests/runnables/test_context.py
+++ b/libs/core/tests/unit_tests/runnables/test_context.py
@@ -332,7 +332,8 @@ test_cases = [
 
 @pytest.mark.parametrize(("runnable", "cases"), test_cases)
 def test_context_runnables(
-    runnable: Union[Runnable, Callable[[], Runnable]], cases: list[_TestCase]
+    runnable: Union[Runnable[Any, Any], Callable[[], Runnable[Any, Any]]],
+    cases: list[_TestCase],
 ) -> None:
     runnable = runnable if isinstance(runnable, Runnable) else runnable()
     assert runnable.invoke(cases[0].input) == cases[0].output
@@ -344,7 +345,8 @@ def test_context_runnables(
 
 @pytest.mark.parametrize(("runnable", "cases"), test_cases)
 async def test_context_runnables_async(
-    runnable: Union[Runnable, Callable[[], Runnable]], cases: list[_TestCase]
+    runnable: Union[Runnable[Any, Any], Callable[[], Runnable[Any, Any]]],
+    cases: list[_TestCase],
 ) -> None:
     runnable = runnable if isinstance(runnable, Runnable) else runnable()
     assert await runnable.ainvoke(cases[1].input) == cases[1].output
diff --git a/libs/core/tests/unit_tests/runnables/test_fallbacks.py b/libs/core/tests/unit_tests/runnables/test_fallbacks.py
index 3985facc544..e0666fbf744 100644
--- a/libs/core/tests/unit_tests/runnables/test_fallbacks.py
+++ b/libs/core/tests/unit_tests/runnables/test_fallbacks.py
@@ -34,7 +34,7 @@ from langchain_core.tools import BaseTool
 
 
 @pytest.fixture
-def llm() -> RunnableWithFallbacks:
+def llm() -> RunnableWithFallbacks[Any, Any]:
     error_llm = FakeListLLM(responses=["foo"], i=1)
     pass_llm = FakeListLLM(responses=["bar"])
 
@@ -42,7 +42,7 @@ def llm() -> RunnableWithFallbacks:
 
 
 @pytest.fixture
-def llm_multi() -> RunnableWithFallbacks:
+def llm_multi() -> RunnableWithFallbacks[Any, Any]:
     error_llm = FakeListLLM(responses=["foo"], i=1)
     error_llm_2 = FakeListLLM(responses=["baz"], i=1)
     pass_llm = FakeListLLM(responses=["bar"])
@@ -51,7 +51,7 @@ def llm_multi() -> RunnableWithFallbacks:
 
 
 @pytest.fixture
-def chain() -> Runnable:
+def chain() -> Runnable[Any, str]:
     error_llm = FakeListLLM(responses=["foo"], i=1)
     pass_llm = FakeListLLM(responses=["bar"])
 
@@ -61,18 +61,18 @@ def chain() -> Runnable:
     )
 
 
-def _raise_error(_: dict) -> str:
+def _raise_error(_: dict[str, Any]) -> str:
     raise ValueError
 
 
-def _dont_raise_error(inputs: dict) -> str:
+def _dont_raise_error(inputs: dict[str, Any]) -> str:
     if "exception" in inputs:
         return "bar"
     raise ValueError
 
 
 @pytest.fixture
-def chain_pass_exceptions() -> Runnable:
+def chain_pass_exceptions() -> Runnable[Any, str]:
     fallback = RunnableLambda(_dont_raise_error)
     return {"text": RunnablePassthrough()} | RunnableLambda(
         _raise_error
@@ -80,13 +80,13 @@ def chain_pass_exceptions() -> Runnable:
 
 
 @pytest.mark.parametrize(
-    "runnable",
+    "runnable_name",
     ["llm", "llm_multi", "chain", "chain_pass_exceptions"],
 )
 def test_fallbacks(
-    runnable: RunnableWithFallbacks, request: Any, snapshot: SnapshotAssertion
+    runnable_name: str, request: Any, snapshot: SnapshotAssertion
 ) -> None:
-    runnable = request.getfixturevalue(runnable)
+    runnable: Runnable[Any, Any] = request.getfixturevalue(runnable_name)
     assert runnable.invoke("hello") == "bar"
     assert runnable.batch(["hi", "hey", "bye"]) == ["bar"] * 3
     assert list(runnable.stream("hello")) == ["bar"]
@@ -94,17 +94,17 @@ def test_fallbacks(
 
 
 @pytest.mark.parametrize(
-    "runnable",
+    "runnable_name",
     ["llm", "llm_multi", "chain", "chain_pass_exceptions"],
 )
-async def test_fallbacks_async(runnable: RunnableWithFallbacks, request: Any) -> None:
-    runnable = request.getfixturevalue(runnable)
+async def test_fallbacks_async(runnable_name: str, request: Any) -> None:
+    runnable: Runnable[Any, Any] = request.getfixturevalue(runnable_name)
     assert await runnable.ainvoke("hello") == "bar"
     assert await runnable.abatch(["hi", "hey", "bye"]) == ["bar"] * 3
     assert list(await runnable.ainvoke("hello")) == list("bar")
 
 
-def _runnable(inputs: dict) -> str:
+def _runnable(inputs: dict[str, Any]) -> str:
     if inputs["text"] == "foo":
         return "first"
     if "exception" not in inputs:
@@ -117,7 +117,7 @@ def _runnable(inputs: dict) -> str:
     return "third"
 
 
-def _assert_potential_error(actual: list, expected: list) -> None:
+def _assert_potential_error(actual: list[Any], expected: list[Any]) -> None:
     for x, y in zip(actual, expected):
         if isinstance(x, Exception):
             assert isinstance(y, type(x))
@@ -260,17 +260,17 @@ async def test_abatch() -> None:
     _assert_potential_error(actual, expected)
 
 
-def _generate(_: Iterator) -> Iterator[str]:
+def _generate(_: Iterator[Any]) -> Iterator[str]:
     yield from "foo bar"
 
 
-def _generate_immediate_error(_: Iterator) -> Iterator[str]:
+def _generate_immediate_error(_: Iterator[Any]) -> Iterator[str]:
     msg = "immmediate error"
     raise ValueError(msg)
     yield ""
 
 
-def _generate_delayed_error(_: Iterator) -> Iterator[str]:
+def _generate_delayed_error(_: Iterator[Any]) -> Iterator[str]:
     yield ""
     msg = "delayed error"
     raise ValueError(msg)
@@ -289,18 +289,18 @@ def test_fallbacks_stream() -> None:
         list(runnable.stream({}))
 
 
-async def _agenerate(_: AsyncIterator) -> AsyncIterator[str]:
+async def _agenerate(_: AsyncIterator[Any]) -> AsyncIterator[str]:
     for c in "foo bar":
         yield c
 
 
-async def _agenerate_immediate_error(_: AsyncIterator) -> AsyncIterator[str]:
+async def _agenerate_immediate_error(_: AsyncIterator[Any]) -> AsyncIterator[str]:
     msg = "immmediate error"
     raise ValueError(msg)
     yield ""
 
 
-async def _agenerate_delayed_error(_: AsyncIterator) -> AsyncIterator[str]:
+async def _agenerate_delayed_error(_: AsyncIterator[Any]) -> AsyncIterator[str]:
     yield ""
     msg = "delayed error"
     raise ValueError(msg)
@@ -346,7 +346,7 @@ class FakeStructuredOutputModel(BaseChatModel):
     @override
     def with_structured_output(
         self, schema: Union[dict, type[BaseModel]], **kwargs: Any
-    ) -> Runnable[LanguageModelInput, Union[dict, BaseModel]]:
+    ) -> Runnable[Any, dict[str, int]]:
         return RunnableLambda(lambda _: {"foo": self.foo})
 
     @property
diff --git a/libs/core/tests/unit_tests/runnables/test_graph.py b/libs/core/tests/unit_tests/runnables/test_graph.py
index 7944d0b1da4..3e2d25f41fa 100644
--- a/libs/core/tests/unit_tests/runnables/test_graph.py
+++ b/libs/core/tests/unit_tests/runnables/test_graph.py
@@ -1,4 +1,4 @@
-from typing import Any, Optional
+from typing import Any, Optional, Union
 
 from packaging import version
 from pydantic import BaseModel
@@ -6,6 +6,7 @@ from syrupy.assertion import SnapshotAssertion
 from typing_extensions import override
 
 from langchain_core.language_models import FakeListLLM
+from langchain_core.messages import BaseMessage
 from langchain_core.output_parsers.list import CommaSeparatedListOutputParser
 from langchain_core.output_parsers.string import StrOutputParser
 from langchain_core.output_parsers.xml import XMLOutputParser
@@ -222,7 +223,7 @@ def test_graph_sequence_map(snapshot: SnapshotAssertion) -> None:
     str_parser = StrOutputParser()
     xml_parser = XMLOutputParser()
 
-    def conditional_str_parser(value: str) -> Runnable:
+    def conditional_str_parser(value: str) -> Runnable[Union[BaseMessage, str], str]:
         if value == "a":
             return str_parser
         return xml_parser
@@ -528,7 +529,7 @@ def test_graph_mermaid_escape_node_label() -> None:
 
 def test_graph_mermaid_duplicate_nodes(snapshot: SnapshotAssertion) -> None:
     fake_llm = FakeListLLM(responses=["foo", "bar"])
-    sequence: Runnable = (
+    sequence = (
         PromptTemplate.from_template("Hello, {input}")
         | {
             "llm1": fake_llm,
diff --git a/libs/core/tests/unit_tests/runnables/test_history.py b/libs/core/tests/unit_tests/runnables/test_history.py
index 0a4b5326ff3..7b0c368bab1 100644
--- a/libs/core/tests/unit_tests/runnables/test_history.py
+++ b/libs/core/tests/unit_tests/runnables/test_history.py
@@ -35,7 +35,7 @@ def test_interfaces() -> None:
 
 def _get_get_session_history(
     *,
-    store: Optional[dict[str, Any]] = None,
+    store: Optional[dict[str, InMemoryChatMessageHistory]] = None,
 ) -> Callable[..., InMemoryChatMessageHistory]:
     chat_history_store = store if store is not None else {}
 
@@ -54,7 +54,7 @@ def test_input_messages() -> None:
         lambda messages: "you said: "
         + "\n".join(str(m.content) for m in messages if isinstance(m, HumanMessage))
     )
-    store: dict = {}
+    store: dict[str, InMemoryChatMessageHistory] = {}
     get_session_history = _get_get_session_history(store=store)
     with_history = RunnableWithMessageHistory(runnable, get_session_history)
     config: RunnableConfig = {"configurable": {"session_id": "1"}}
@@ -83,7 +83,7 @@ async def test_input_messages_async() -> None:
         lambda messages: "you said: "
         + "\n".join(str(m.content) for m in messages if isinstance(m, HumanMessage))
     )
-    store: dict = {}
+    store: dict[str, InMemoryChatMessageHistory] = {}
     get_session_history = _get_get_session_history(store=store)
     with_history = RunnableWithMessageHistory(runnable, get_session_history)
     config = {"session_id": "1_async"}
@@ -489,7 +489,7 @@ def test_get_output_schema() -> None:
     )
     output_type = with_history.get_output_schema()
 
-    expected_schema: dict = {
+    expected_schema: dict[str, Any] = {
         "title": "RunnableWithChatHistoryOutput",
         "type": "object",
     }
@@ -842,8 +842,7 @@ def test_get_output_messages_no_value_error() -> None:
         lambda messages: "you said: "
         + "\n".join(str(m.content) for m in messages if isinstance(m, HumanMessage))
     )
-    store: dict = {}
-    get_session_history = _get_get_session_history(store=store)
+    get_session_history = _get_get_session_history()
     with_history = RunnableWithMessageHistory(runnable, get_session_history)
     config: RunnableConfig = {
         "configurable": {"session_id": "1", "message_history": get_session_history("1")}
@@ -859,8 +858,7 @@ def test_get_output_messages_no_value_error() -> None:
 def test_get_output_messages_with_value_error() -> None:
     illegal_bool_message = False
     runnable = _RunnableLambdaWithRaiseError(lambda _: illegal_bool_message)
-    store: dict = {}
-    get_session_history = _get_get_session_history(store=store)
+    get_session_history = _get_get_session_history()
     with_history = RunnableWithMessageHistory(runnable, get_session_history)  # type: ignore[arg-type]
     config: RunnableConfig = {
         "configurable": {"session_id": "1", "message_history": get_session_history("1")}
diff --git a/libs/core/tests/unit_tests/runnables/test_runnable.py b/libs/core/tests/unit_tests/runnables/test_runnable.py
index 4b63fb50ae2..920b1ff9af1 100644
--- a/libs/core/tests/unit_tests/runnables/test_runnable.py
+++ b/libs/core/tests/unit_tests/runnables/test_runnable.py
@@ -513,7 +513,7 @@ def test_passthrough_assign_schema() -> None:
     prompt = PromptTemplate.from_template("{context} {question}")
     fake_llm = FakeListLLM(responses=["a"])  # str -> list[list[str]]
 
-    seq_w_assign: Runnable = (
+    seq_w_assign = (
         RunnablePassthrough.assign(context=itemgetter("question") | retriever)
         | prompt
         | fake_llm
@@ -530,7 +530,7 @@ def test_passthrough_assign_schema() -> None:
         "type": "string",
     }
 
-    invalid_seq_w_assign: Runnable = (
+    invalid_seq_w_assign = (
         RunnablePassthrough.assign(context=itemgetter("question") | retriever)
         | fake_llm
     )
@@ -1011,7 +1011,7 @@ def test_passthrough_tap(mocker: MockerFixture) -> None:
     fake = FakeRunnable()
     mock = mocker.Mock()
 
-    seq: Runnable = RunnablePassthrough(mock) | fake | RunnablePassthrough(mock)
+    seq = RunnablePassthrough[Any](mock) | fake | RunnablePassthrough[Any](mock)
 
     assert seq.invoke("hello", my_kwarg="value") == 5
     assert mock.call_args_list == [
@@ -1078,7 +1078,7 @@ async def test_passthrough_tap_async(mocker: MockerFixture) -> None:
     fake = FakeRunnable()
     mock = mocker.Mock()
 
-    seq: Runnable = RunnablePassthrough(mock) | fake | RunnablePassthrough(mock)
+    seq = RunnablePassthrough[Any](mock) | fake | RunnablePassthrough[Any](mock)
 
     assert await seq.ainvoke("hello", my_kwarg="value") == 5
     assert mock.call_args_list == [
@@ -1188,8 +1188,8 @@ def test_with_config(mocker: MockerFixture) -> None:
     ]
     spy.reset_mock()
 
-    fake_1: Runnable = RunnablePassthrough()
-    fake_2: Runnable = RunnablePassthrough()
+    fake_1 = RunnablePassthrough[Any]()
+    fake_2 = RunnablePassthrough[Any]()
     spy_seq_step = mocker.spy(fake_1.__class__, "invoke")
 
     sequence = fake_1.with_config(tags=["a-tag"]) | fake_2.with_config(
@@ -1650,7 +1650,7 @@ def test_with_listeners(mocker: MockerFixture) -> None:
     )
     chat = FakeListChatModel(responses=["foo"])
 
-    chain: Runnable = prompt | chat
+    chain = prompt | chat
 
     mock_start = mocker.Mock()
     mock_end = mocker.Mock()
@@ -1683,7 +1683,7 @@ async def test_with_listeners_async(mocker: MockerFixture) -> None:
     )
     chat = FakeListChatModel(responses=["foo"])
 
-    chain: Runnable = prompt | chat
+    chain = prompt | chat
 
     mock_start = mocker.Mock()
     mock_end = mocker.Mock()
@@ -1787,7 +1787,7 @@ def test_prompt_with_chat_model(
     )
     chat = FakeListChatModel(responses=["foo"])
 
-    chain: Runnable = prompt | chat
+    chain = prompt | chat
 
     assert repr(chain) == snapshot
     assert isinstance(chain, RunnableSequence)
@@ -1893,7 +1893,7 @@ async def test_prompt_with_chat_model_async(
     )
     chat = FakeListChatModel(responses=["foo"])
 
-    chain: Runnable = prompt | chat
+    chain = prompt | chat
 
     assert repr(chain) == snapshot
     assert isinstance(chain, RunnableSequence)
@@ -2007,7 +2007,7 @@ async def test_prompt_with_llm(
     )
     llm = FakeListLLM(responses=["foo", "bar"])
 
-    chain: Runnable = prompt | llm
+    chain = prompt | llm
 
     assert isinstance(chain, RunnableSequence)
     assert chain.first == prompt
@@ -2204,7 +2204,7 @@ async def test_prompt_with_llm_parser(
     llm = FakeStreamingListLLM(responses=["bear, dog, cat", "tomato, lettuce, onion"])
     parser = CommaSeparatedListOutputParser()
 
-    chain: Runnable = prompt | llm | parser
+    chain = prompt | llm | parser
 
     assert isinstance(chain, RunnableSequence)
     assert chain.first == prompt
@@ -2517,7 +2517,7 @@ async def test_stream_log_lists() -> None:
         for i in range(4):
             yield AddableDict(alist=[str(i)])
 
-    chain: Runnable = RunnableGenerator(list_producer)
+    chain = RunnableGenerator(list_producer)
 
     stream_log = [
         part async for part in chain.astream_log({"question": "What is your name?"})
@@ -2697,7 +2697,7 @@ def test_combining_sequences(
 
     chain2 = cast("RunnableSequence", input_formatter | prompt2 | chat2 | parser2)
 
-    assert isinstance(chain, RunnableSequence)
+    assert isinstance(chain2, RunnableSequence)
     assert chain2.first == input_formatter
     assert chain2.middle == [prompt2, chat2]
     assert chain2.last == parser2
@@ -2705,6 +2705,7 @@ def test_combining_sequences(
 
     combined_chain = cast("RunnableSequence", chain | chain2)
 
+    assert isinstance(combined_chain, RunnableSequence)
     assert combined_chain.first == prompt
     assert combined_chain.middle == [
         chat,
@@ -2869,13 +2870,13 @@ def test_seq_prompt_dict(mocker: MockerFixture, snapshot: SnapshotAssertion) ->
 
 @freeze_time("2023-01-01")
 def test_router_runnable(mocker: MockerFixture, snapshot: SnapshotAssertion) -> None:
-    chain1: Runnable = ChatPromptTemplate.from_template(
+    chain1 = ChatPromptTemplate.from_template(
         "You are a math genius. Answer the question: {question}"
     ) | FakeListLLM(responses=["4"])
-    chain2: Runnable = ChatPromptTemplate.from_template(
+    chain2 = ChatPromptTemplate.from_template(
         "You are an english major. Answer the question: {question}"
     ) | FakeListLLM(responses=["2"])
-    router: Runnable = RouterRunnable({"math": chain1, "english": chain2})
+    router = RouterRunnable({"math": chain1, "english": chain2})
     chain: Runnable = {
         "key": lambda x: x["key"],
         "input": {"question": lambda x: x["question"]},
@@ -2913,13 +2914,13 @@ def test_router_runnable(mocker: MockerFixture, snapshot: SnapshotAssertion) ->
 
 
 async def test_router_runnable_async() -> None:
-    chain1: Runnable = ChatPromptTemplate.from_template(
+    chain1 = ChatPromptTemplate.from_template(
         "You are a math genius. Answer the question: {question}"
     ) | FakeListLLM(responses=["4"])
-    chain2: Runnable = ChatPromptTemplate.from_template(
+    chain2 = ChatPromptTemplate.from_template(
         "You are an english major. Answer the question: {question}"
     ) | FakeListLLM(responses=["2"])
-    router: Runnable = RouterRunnable({"math": chain1, "english": chain2})
+    router = RouterRunnable({"math": chain1, "english": chain2})
     chain: Runnable = {
         "key": lambda x: x["key"],
         "input": {"question": lambda x: x["question"]},
@@ -2941,13 +2942,13 @@ async def test_router_runnable_async() -> None:
 def test_higher_order_lambda_runnable(
     mocker: MockerFixture, snapshot: SnapshotAssertion
 ) -> None:
-    math_chain: Runnable = ChatPromptTemplate.from_template(
+    math_chain = ChatPromptTemplate.from_template(
         "You are a math genius. Answer the question: {question}"
     ) | FakeListLLM(responses=["4"])
-    english_chain: Runnable = ChatPromptTemplate.from_template(
+    english_chain = ChatPromptTemplate.from_template(
         "You are an english major. Answer the question: {question}"
     ) | FakeListLLM(responses=["2"])
-    input_map: Runnable = RunnableParallel(
+    input_map = RunnableParallel(
         key=lambda x: x["key"],
         input={"question": lambda x: x["question"]},
     )
@@ -2997,13 +2998,13 @@ def test_higher_order_lambda_runnable(
 
 
 async def test_higher_order_lambda_runnable_async(mocker: MockerFixture) -> None:
-    math_chain: Runnable = ChatPromptTemplate.from_template(
+    math_chain = ChatPromptTemplate.from_template(
         "You are a math genius. Answer the question: {question}"
     ) | FakeListLLM(responses=["4"])
-    english_chain: Runnable = ChatPromptTemplate.from_template(
+    english_chain = ChatPromptTemplate.from_template(
         "You are an english major. Answer the question: {question}"
     ) | FakeListLLM(responses=["2"])
-    input_map: Runnable = RunnableParallel(
+    input_map = RunnableParallel(
         key=lambda x: x["key"],
         input={"question": lambda x: x["question"]},
     )
@@ -3779,7 +3780,7 @@ async def test_deep_astream_assign() -> None:
 def test_runnable_sequence_transform() -> None:
     llm = FakeStreamingListLLM(responses=["foo-lish"])
 
-    chain: Runnable = llm | StrOutputParser()
+    chain = llm | StrOutputParser()
 
     stream = chain.transform(llm.stream("Hi there!"))
 
@@ -3792,7 +3793,7 @@ def test_runnable_sequence_transform() -> None:
 async def test_runnable_sequence_atransform() -> None:
     llm = FakeStreamingListLLM(responses=["foo-lish"])
 
-    chain: Runnable = llm | StrOutputParser()
+    chain = llm | StrOutputParser()
 
     stream = chain.atransform(llm.astream("Hi there!"))
 
@@ -3867,7 +3868,7 @@ def test_recursive_lambda() -> None:
 
 
 def test_retrying(mocker: MockerFixture) -> None:
-    def _lambda(x: int) -> Union[int, Runnable]:
+    def _lambda(x: int) -> int:
         if x == 1:
             msg = "x is 1"
             raise ValueError(msg)
@@ -3932,7 +3933,7 @@ def test_retrying(mocker: MockerFixture) -> None:
 
 
 async def test_async_retrying(mocker: MockerFixture) -> None:
-    def _lambda(x: int) -> Union[int, Runnable]:
+    def _lambda(x: int) -> int:
         if x == 1:
             msg = "x is 1"
             raise ValueError(msg)
@@ -4046,7 +4047,7 @@ async def test_runnable_lambda_astream() -> None:
     """Test that astream works for both normal functions & those returning Runnable."""
 
     # Wrapper to make a normal function async
-    def awrapper(func: Callable) -> Callable[..., Awaitable[Any]]:
+    def awrapper(func: Callable[..., Any]) -> Callable[..., Awaitable[Any]]:
         async def afunc(*args: Any, **kwargs: Any) -> Any:
             return func(*args, **kwargs)
 
@@ -4140,8 +4141,8 @@ def test_seq_batch_return_exceptions(mocker: MockerFixture) -> None:
         def _batch(
             self,
             inputs: list[str],
-        ) -> list:
-            outputs: list[Any] = []
+        ) -> list[Union[str, Exception]]:
+            outputs: list[Union[str, Exception]] = []
             for value in inputs:
                 if value.startswith(self.fail_starts_with):
                     outputs.append(
@@ -4281,8 +4282,8 @@ async def test_seq_abatch_return_exceptions(mocker: MockerFixture) -> None:
         async def _abatch(
             self,
             inputs: list[str],
-        ) -> list:
-            outputs: list[Any] = []
+        ) -> list[Union[str, Exception]]:
+            outputs: list[Union[str, Exception]] = []
             for value in inputs:
                 if value.startswith(self.fail_starts_with):
                     outputs.append(
@@ -5534,7 +5535,7 @@ def test_listeners() -> None:
     from langchain_core.runnables import RunnableLambda
     from langchain_core.tracers.schemas import Run
 
-    def fake_chain(inputs: dict) -> dict:
+    def fake_chain(inputs: dict[str, str]) -> dict[str, str]:
         return {**inputs, "key": "extra"}
 
     shared_state = {}
@@ -5564,7 +5565,7 @@ async def test_listeners_async() -> None:
     from langchain_core.runnables import RunnableLambda
     from langchain_core.tracers.schemas import Run
 
-    def fake_chain(inputs: dict) -> dict:
+    def fake_chain(inputs: dict[str, str]) -> dict[str, str]:
         return {**inputs, "key": "extra"}
 
     shared_state = {}
@@ -5577,7 +5578,7 @@ async def test_listeners_async() -> None:
     def on_end(run: Run) -> None:
         shared_state[run.id]["outputs"] = run.inputs
 
-    chain: Runnable = (
+    chain = (
         RunnableLambda(fake_chain)
         .with_listeners(on_end=on_end, on_start=on_start)
         .map()
@@ -5647,7 +5648,7 @@ def test_pydantic_protected_namespaces() -> None:
     with warnings.catch_warnings():
         warnings.simplefilter("error")
 
-        class CustomChatModel(RunnableSerializable):
+        class CustomChatModel(RunnableSerializable[str, str]):
             model_kwargs: dict[str, Any] = Field(default_factory=dict)
 
 
diff --git a/libs/core/tests/unit_tests/runnables/test_runnable_events_v1.py b/libs/core/tests/unit_tests/runnables/test_runnable_events_v1.py
index b41409754a3..984126ca149 100644
--- a/libs/core/tests/unit_tests/runnables/test_runnable_events_v1.py
+++ b/libs/core/tests/unit_tests/runnables/test_runnable_events_v1.py
@@ -2,7 +2,7 @@
 
 import asyncio
 import sys
-from collections.abc import AsyncIterator, Sequence
+from collections.abc import AsyncIterator, Mapping, Sequence
 from itertools import cycle
 from typing import Any, cast
 
@@ -44,12 +44,6 @@ def _with_nulled_run_id(events: Sequence[StreamEvent]) -> list[StreamEvent]:
     return cast("list[StreamEvent]", [{**event, "run_id": ""} for event in events])
 
 
-async def _as_async_iterator(iterable: list) -> AsyncIterator:
-    """Converts an iterable into an async iterator."""
-    for item in iterable:
-        yield item
-
-
 async def _collect_events(events: AsyncIterator[StreamEvent]) -> list[StreamEvent]:
     """Collect the events and remove the run ids."""
     materialized_events = [event async for event in events]
@@ -59,7 +53,9 @@ async def _collect_events(events: AsyncIterator[StreamEvent]) -> list[StreamEven
     return events_
 
 
-def _assert_events_equal_allow_superset_metadata(events: list, expected: list) -> None:
+def _assert_events_equal_allow_superset_metadata(
+    events: Sequence[Mapping[str, Any]], expected: Sequence[Mapping[str, Any]]
+) -> None:
     """Assert that the events are equal."""
     assert len(events) == len(expected)
     for i, (event, expected_event) in enumerate(zip(events, expected)):
@@ -1910,7 +1906,7 @@ async def test_runnable_with_message_history() -> None:
 
     # Here we use a global variable to store the chat message history.
     # This will make it easier to inspect it to see the underlying results.
-    store: dict = {}
+    store: dict[str, list[BaseMessage]] = {}
 
     def get_by_session_id(session_id: str) -> BaseChatMessageHistory:
         """Get a chat message history."""
diff --git a/libs/core/tests/unit_tests/runnables/test_runnable_events_v2.py b/libs/core/tests/unit_tests/runnables/test_runnable_events_v2.py
index a7731053032..72f183a5d66 100644
--- a/libs/core/tests/unit_tests/runnables/test_runnable_events_v2.py
+++ b/libs/core/tests/unit_tests/runnables/test_runnable_events_v2.py
@@ -74,12 +74,6 @@ def _with_nulled_run_id(events: Sequence[StreamEvent]) -> list[StreamEvent]:
     )
 
 
-async def _as_async_iterator(iterable: list) -> AsyncIterator:
-    """Converts an iterable into an async iterator."""
-    for item in iterable:
-        yield item
-
-
 async def _collect_events(
     events: AsyncIterator[StreamEvent], *, with_nulled_ids: bool = True
 ) -> list[StreamEvent]:
@@ -1866,7 +1860,7 @@ async def test_runnable_with_message_history() -> None:
 
     # Here we use a global variable to store the chat message history.
     # This will make it easier to inspect it to see the underlying results.
-    store: dict = {}
+    store: dict[str, list[BaseMessage]] = {}
 
     def get_by_session_id(session_id: str) -> BaseChatMessageHistory:
         """Get a chat message history."""
diff --git a/libs/core/tests/unit_tests/runnables/test_tracing_interops.py b/libs/core/tests/unit_tests/runnables/test_tracing_interops.py
index 08a846827f3..de555d4e4de 100644
--- a/libs/core/tests/unit_tests/runnables/test_tracing_interops.py
+++ b/libs/core/tests/unit_tests/runnables/test_tracing_interops.py
@@ -20,7 +20,7 @@ from langchain_core.runnables.base import RunnableLambda, RunnableParallel
 from langchain_core.tracers.langchain import LangChainTracer
 
 
-def _get_posts(client: Client) -> list:
+def _get_posts(client: Client) -> list[dict[str, Any]]:
     mock_calls = client.session.request.mock_calls  # type: ignore[attr-defined]
     posts = []
     for call in mock_calls:
@@ -274,7 +274,7 @@ class TestRunnableSequenceParallelTraceNesting:
         def before(x: int) -> int:
             return x
 
-        def after(x: dict) -> int:
+        def after(x: dict[str, Any]) -> int:
             return x["chain_result"]
 
         sequence = before | parallel | after
diff --git a/libs/core/tests/unit_tests/runnables/test_utils.py b/libs/core/tests/unit_tests/runnables/test_utils.py
index af2b603ec35..edd0abd7269 100644
--- a/libs/core/tests/unit_tests/runnables/test_utils.py
+++ b/libs/core/tests/unit_tests/runnables/test_utils.py
@@ -1,5 +1,5 @@
 import sys
-from typing import Callable
+from typing import Any, Callable
 
 import pytest
 
@@ -22,7 +22,7 @@ from langchain_core.runnables.utils import (
         (lambda x: x if x > 0 else 0, "lambda x: x if x > 0 else 0"),  # noqa: FURB136
     ],
 )
-def test_get_lambda_source(func: Callable, expected_source: str) -> None:
+def test_get_lambda_source(func: Callable[..., Any], expected_source: str) -> None:
     """Test get_lambda_source function."""
     source = get_lambda_source(func)
     assert source == expected_source
diff --git a/libs/core/tests/unit_tests/stores/test_in_memory.py b/libs/core/tests/unit_tests/stores/test_in_memory.py
index cc8ec684fbe..6034f59cdab 100644
--- a/libs/core/tests/unit_tests/stores/test_in_memory.py
+++ b/libs/core/tests/unit_tests/stores/test_in_memory.py
@@ -1,3 +1,5 @@
+from typing import Any
+
 import pytest
 from langchain_tests.integration_tests.base_store import (
     BaseStoreAsyncTests,
@@ -8,7 +10,7 @@ from langchain_core.stores import InMemoryStore
 
 
 # Check against standard tests
-class TestSyncInMemoryStore(BaseStoreSyncTests):
+class TestSyncInMemoryStore(BaseStoreSyncTests[Any]):
     @pytest.fixture
     def kv_store(self) -> InMemoryStore:
         return InMemoryStore()
diff --git a/libs/core/tests/unit_tests/test_tools.py b/libs/core/tests/unit_tests/test_tools.py
index f5cc42e1b4d..c2fbba2e8ef 100644
--- a/libs/core/tests/unit_tests/test_tools.py
+++ b/libs/core/tests/unit_tests/test_tools.py
@@ -39,7 +39,6 @@ from langchain_core.messages import ToolCall, ToolMessage
 from langchain_core.messages.tool import ToolOutputMixin
 from langchain_core.retrievers import BaseRetriever
 from langchain_core.runnables import (
-    Runnable,
     RunnableConfig,
     RunnableLambda,
     ensure_config,
@@ -72,7 +71,7 @@ from tests.unit_tests.fake.callbacks import FakeCallbackHandler
 from tests.unit_tests.pydantic_utils import _schema
 
 
-def _get_tool_call_json_schema(tool: BaseTool) -> dict:
+def _get_tool_call_json_schema(tool: BaseTool) -> dict[str, Any]:
     tool_schema = tool.tool_call_schema
     if isinstance(tool_schema, dict):
         return tool_schema
@@ -1402,15 +1401,15 @@ class _MockStructuredToolWithRawOutput(BaseTool):
         self,
         arg1: int,
         arg2: bool,  # noqa: FBT001
-        arg3: Optional[dict] = None,
-    ) -> tuple[str, dict]:
+        arg3: Optional[dict[str, str]] = None,
+    ) -> tuple[str, dict[str, Any]]:
         return f"{arg1} {arg2}", {"arg1": arg1, "arg2": arg2, "arg3": arg3}
 
 
 @tool("structured_api", response_format="content_and_artifact")
 def _mock_structured_tool_with_artifact(
-    *, arg1: int, arg2: bool, arg3: Optional[dict] = None
-) -> tuple[str, dict]:
+    *, arg1: int, arg2: bool, arg3: Optional[dict[str, str]] = None
+) -> tuple[str, dict[str, Any]]:
     """A Structured Tool."""
     return f"{arg1} {arg2}", {"arg1": arg1, "arg2": arg2, "arg3": arg3}
 
@@ -1419,7 +1418,7 @@ def _mock_structured_tool_with_artifact(
     "tool", [_MockStructuredToolWithRawOutput(), _mock_structured_tool_with_artifact]
 )
 def test_tool_call_input_tool_message_with_artifact(tool: BaseTool) -> None:
-    tool_call: dict = {
+    tool_call: dict[str, Any] = {
         "name": "structured_api",
         "args": {"arg1": 1, "arg2": True, "arg3": {"img": "base64string..."}},
         "id": "123",
@@ -1448,7 +1447,7 @@ def test_convert_from_runnable_dict() -> None:
     def f(x: Args) -> str:
         return str(x["a"] * max(x["b"]))
 
-    runnable: Runnable = RunnableLambda(f)
+    runnable = RunnableLambda(f)
     as_tool = runnable.as_tool()
     args_schema = as_tool.args_schema
     assert args_schema is not None
@@ -1480,14 +1479,14 @@ def test_convert_from_runnable_dict() -> None:
         a: int = Field(..., description="Integer")
         b: list[int] = Field(..., description="List of ints")
 
-    runnable = RunnableLambda(g)
-    as_tool = runnable.as_tool(GSchema)
-    as_tool.invoke({"a": 3, "b": [1, 2]})
+    runnable2 = RunnableLambda(g)
+    as_tool2 = runnable2.as_tool(GSchema)
+    as_tool2.invoke({"a": 3, "b": [1, 2]})
 
     # Specify via arg_types:
-    runnable = RunnableLambda(g)
-    as_tool = runnable.as_tool(arg_types={"a": int, "b": list[int]})
-    result = as_tool.invoke({"a": 3, "b": [1, 2]})
+    runnable3 = RunnableLambda(g)
+    as_tool3 = runnable3.as_tool(arg_types={"a": int, "b": list[int]})
+    result = as_tool3.invoke({"a": 3, "b": [1, 2]})
     assert result == "6"
 
     # Test with config
@@ -1496,9 +1495,9 @@ def test_convert_from_runnable_dict() -> None:
         assert config["configurable"]["foo"] == "not-bar"
         return str(x["a"] * max(x["b"]))
 
-    runnable = RunnableLambda(h)
-    as_tool = runnable.as_tool(arg_types={"a": int, "b": list[int]})
-    result = as_tool.invoke(
+    runnable4 = RunnableLambda(h)
+    as_tool4 = runnable4.as_tool(arg_types={"a": int, "b": list[int]})
+    result = as_tool4.invoke(
         {"a": 3, "b": [1, 2]}, config={"configurable": {"foo": "not-bar"}}
     )
     assert result == "6"
@@ -1512,7 +1511,7 @@ def test_convert_from_runnable_other() -> None:
     def g(x: str) -> str:
         return x + "z"
 
-    runnable: Runnable = RunnableLambda(f) | g
+    runnable = RunnableLambda(f) | g
     as_tool = runnable.as_tool()
     args_schema = as_tool.args_schema
     assert args_schema is None
@@ -1527,10 +1526,10 @@ def test_convert_from_runnable_other() -> None:
         assert config["configurable"]["foo"] == "not-bar"
         return x + "a"
 
-    runnable = RunnableLambda(h)
-    as_tool = runnable.as_tool()
-    result = as_tool.invoke("b", config={"configurable": {"foo": "not-bar"}})
-    assert result == "ba"
+    runnable2 = RunnableLambda(h)
+    as_tool2 = runnable2.as_tool()
+    result2 = as_tool2.invoke("b", config={"configurable": {"foo": "not-bar"}})
+    assert result2 == "ba"
 
 
 @tool("foo", parse_docstring=True)
@@ -1785,7 +1784,7 @@ def test_tool_inherited_injected_arg() -> None:
     }
 
 
-def _get_parametrized_tools() -> list:
+def _get_parametrized_tools() -> list[Callable[..., Any]]:
     def my_tool(x: int, y: str, some_tool: Annotated[Any, InjectedToolArg]) -> str:
         """my_tool."""
         return some_tool
@@ -1800,7 +1799,7 @@ def _get_parametrized_tools() -> list:
 
 
 @pytest.mark.parametrize("tool_", _get_parametrized_tools())
-def test_fn_injected_arg_with_schema(tool_: Callable) -> None:
+def test_fn_injected_arg_with_schema(tool_: Callable[..., Any]) -> None:
     assert convert_to_openai_function(tool_) == {
         "name": tool_.__name__,
         "description": "my_tool.",
@@ -2528,13 +2527,13 @@ def test_tool_decorator_description() -> None:
 
     assert foo_args_jsons_schema.description == "JSON Schema."
     assert (
-        cast("dict", foo_args_jsons_schema.tool_call_schema)["description"]
+        cast("dict[str, Any]", foo_args_jsons_schema.tool_call_schema)["description"]
         == "JSON Schema."
     )
 
     assert foo_args_jsons_schema_with_description.description == "description"
     assert (
-        cast("dict", foo_args_jsons_schema_with_description.tool_call_schema)[
+        cast("dict[str, Any]", foo_args_jsons_schema_with_description.tool_call_schema)[
             "description"
         ]
         == "description"