diff --git a/libs/langchain_v1/langchain/agents/middleware/shell_tool.py b/libs/langchain_v1/langchain/agents/middleware/shell_tool.py
index e2326640932..1b5029538f5 100644
--- a/libs/langchain_v1/langchain/agents/middleware/shell_tool.py
+++ b/libs/langchain_v1/langchain/agents/middleware/shell_tool.py
@@ -15,7 +15,7 @@ import uuid
 import weakref
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import TYPE_CHECKING, Annotated, Any, Literal, cast
+from typing import TYPE_CHECKING, Annotated, Any, Literal, cast, overload
 
 from langchain_core.messages import ToolMessage
 from langchain_core.runnables import run_in_executor
@@ -758,6 +758,24 @@ class ShellToolMiddleware(AgentMiddleware[ShellToolState[ResponseT], ContextT, R
                 matches_by_type.setdefault(rule.pii_type, []).extend(matches)
         return updated, matches_by_type
 
+    @overload
+    def _run_shell_tool(
+        self,
+        resources: _SessionResources,
+        payload: dict[str, Any],
+        *,
+        tool_call_id: str,
+    ) -> ToolMessage: ...
+
+    @overload
+    def _run_shell_tool(
+        self,
+        resources: _SessionResources,
+        payload: dict[str, Any],
+        *,
+        tool_call_id: None,
+    ) -> str: ...
+
     def _run_shell_tool(
         self,
         resources: _SessionResources,
@@ -853,6 +871,26 @@ class ShellToolMiddleware(AgentMiddleware[ShellToolState[ResponseT], ContextT, R
             artifact=artifact,
         )
 
+    @overload
+    def _format_tool_message(
+        self,
+        content: str,
+        tool_call_id: str,
+        *,
+        status: Literal["success", "error"],
+        artifact: dict[str, Any] | None = None,
+    ) -> ToolMessage: ...
+
+    @overload
+    def _format_tool_message(
+        self,
+        content: str,
+        tool_call_id: None,
+        *,
+        status: Literal["success", "error"],
+        artifact: dict[str, Any] | None = None,
+    ) -> str: ...
+
     def _format_tool_message(
         self,
         content: str,
diff --git a/libs/langchain_v1/pyproject.toml b/libs/langchain_v1/pyproject.toml
index 98c642177a0..11be8694607 100644
--- a/libs/langchain_v1/pyproject.toml
+++ b/libs/langchain_v1/pyproject.toml
@@ -110,10 +110,6 @@ strict = true
 enable_error_code = "deprecated"
 warn_unreachable = true
 
-exclude = [
-    "tests/unit_tests/agents/middleware/",
-]
-
 [[tool.mypy.overrides]]
 module = ["pytest_socket.*", "vcr.*"]
 ignore_missing_imports = true
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_composition.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_composition.py
index 61e609cabf4..009098b9033 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_composition.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_composition.py
@@ -277,7 +277,7 @@ class TestChainModelCallHandlers:
             test: str
 
         state_values = []
-        runtime_values = []
+        runtime_values: list[tuple[str, Runtime[Any]]] = []
 
         def outer(
             request: ModelRequest, handler: Callable[[ModelRequest], ModelResponse]
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_dynamic_tools.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_dynamic_tools.py
index 682eb27aa94..1190099e367 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_dynamic_tools.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_dynamic_tools.py
@@ -6,24 +6,31 @@ that are not declared upfront when creating the agent.
 
 import asyncio
 from collections.abc import Awaitable, Callable
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 import pytest
 from langchain_core.messages import HumanMessage, ToolCall, ToolMessage
 from langchain_core.tools import tool
 from langgraph.checkpoint.memory import InMemorySaver
+from langgraph.graph.state import CompiledStateGraph
 from langgraph.types import Command
 
 from langchain.agents.factory import create_agent
 from langchain.agents.middleware.types import (
     AgentMiddleware,
+    AgentState,
+    InputAgentState,
     ModelCallResult,
     ModelRequest,
     ModelResponse,
+    OutputAgentState,
     ToolCallRequest,
 )
 from tests.unit_tests.agents.model import FakeToolCallingModel
 
+if TYPE_CHECKING:
+    from langchain_core.runnables import RunnableConfig
+
 
 @tool
 def static_tool(value: str) -> str:
@@ -156,7 +163,7 @@ class ConditionalDynamicToolMiddleware(AgentMiddleware):
 
     def _should_add_tool(self, request: ModelRequest) -> bool:
         messages = request.state.get("messages", [])
-        return messages and "calculator" in str(messages[-1].content).lower()
+        return bool(messages) and "calculator" in str(messages[-1].content).lower()
 
     def wrap_model_call(
         self,
@@ -205,10 +212,15 @@ def get_tool_messages(result: dict[str, Any]) -> list[ToolMessage]:
     return [m for m in result["messages"] if isinstance(m, ToolMessage)]
 
 
-async def invoke_agent(agent: Any, message: str, *, use_async: bool) -> dict[str, Any]:
+async def invoke_agent(
+    agent: CompiledStateGraph[AgentState[Any], None, InputAgentState, OutputAgentState[Any]],
+    message: str,
+    *,
+    use_async: bool,
+) -> dict[str, Any]:
     """Invoke agent synchronously or asynchronously based on flag."""
-    input_data = {"messages": [HumanMessage(message)]}
-    config = {"configurable": {"thread_id": "test"}}
+    input_data: InputAgentState = {"messages": [HumanMessage(message)]}
+    config: RunnableConfig = {"configurable": {"thread_id": "test"}}
     if use_async:
         return await agent.ainvoke(input_data, config)
     # Run sync invoke in thread pool to avoid blocking the event loop
@@ -240,7 +252,7 @@ async def test_dynamic_tool_basic(*, use_async: bool, tools: list[Any] | None) -
 
     agent = create_agent(
         model=model,
-        tools=tools,  # type: ignore[arg-type]
+        tools=tools,
         middleware=[DynamicToolMiddleware()],
         checkpointer=InMemorySaver(),
     )
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_framework.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_framework.py
index 0da495ce320..9e170caf482 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_framework.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_framework.py
@@ -1,6 +1,6 @@
 import sys
 from collections.abc import Awaitable, Callable
-from typing import Annotated, Any, Generic
+from typing import TYPE_CHECKING, Annotated, Any
 
 import pytest
 from langchain_core.language_models import GenericFakeChatModel
@@ -14,6 +14,7 @@ from syrupy.assertion import SnapshotAssertion
 from typing_extensions import override
 
 from langchain.agents.factory import create_agent
+from langchain.agents.middleware import InputAgentState
 from langchain.agents.middleware.types import (
     AgentMiddleware,
     AgentState,
@@ -23,7 +24,6 @@ from langchain.agents.middleware.types import (
     OmitFromInput,
     OmitFromOutput,
     PrivateStateAttr,
-    ResponseT,
     after_agent,
     after_model,
     before_agent,
@@ -35,6 +35,9 @@ from langchain.tools import InjectedState
 from tests.unit_tests.agents.messages import _AnyIdHumanMessage, _AnyIdToolMessage
 from tests.unit_tests.agents.model import FakeToolCallingModel
 
+if TYPE_CHECKING:
+    from langchain_core.runnables import RunnableConfig
+
 
 def test_create_agent_invoke(
     sync_checkpointer: BaseCheckpointSaver[str],
@@ -96,8 +99,8 @@ def test_create_agent_invoke(
         checkpointer=sync_checkpointer,
     )
 
-    thread1 = {"configurable": {"thread_id": "1"}}
-    assert agent_one.invoke({"messages": ["hello"]}, thread1) == {
+    thread1: RunnableConfig = {"configurable": {"thread_id": "1"}}
+    assert agent_one.invoke({"messages": [HumanMessage("hello")]}, thread1) == {
         "messages": [
             _AnyIdHumanMessage(content="hello"),
             AIMessage(
@@ -201,8 +204,8 @@ def test_create_agent_jump(
     if isinstance(sync_checkpointer, InMemorySaver):
         assert agent_one.get_graph().draw_mermaid() == snapshot
 
-    thread1 = {"configurable": {"thread_id": "1"}}
-    assert agent_one.invoke({"messages": []}, thread1) == {"messages": []}
+    thread1: RunnableConfig = {"configurable": {"thread_id": "1"}}
+    assert agent_one.invoke(InputAgentState(messages=[]), thread1) == {"messages": []}
     assert calls == ["NoopSeven.before_model", "NoopEight.before_model"]
 
 
@@ -368,6 +371,11 @@ def test_public_private_state_for_custom_middleware() -> None:
         omit_output: Annotated[str, OmitFromOutput]
         private_state: Annotated[str, PrivateStateAttr]
 
+    class CustomInputState(InputAgentState):
+        omit_input: str
+        omit_output: str
+        private_state: str
+
     class CustomMiddleware(AgentMiddleware[CustomState]):
         state_schema: type[CustomState] = CustomState
 
@@ -380,12 +388,12 @@ def test_public_private_state_for_custom_middleware() -> None:
 
     agent = create_agent(model=FakeToolCallingModel(), middleware=[CustomMiddleware()])
     result = agent.invoke(
-        {
-            "messages": [HumanMessage("Hello")],
-            "omit_input": "test in",
-            "private_state": "test in",
-            "omit_output": "test in",
-        }
+        CustomInputState(
+            messages=[HumanMessage("Hello")],
+            omit_input="test in",
+            private_state="test in",
+            omit_output="test in",
+        )
     )
     assert "omit_input" in result
     assert "omit_output" not in result
@@ -420,7 +428,11 @@ def test_runtime_injected_into_middleware() -> None:
 # custom state w/in a function
 
 
-class CustomState(AgentState[ResponseT], Generic[ResponseT]):
+class CustomState(AgentState[Any]):
+    custom_state: str
+
+
+class _CustomInputState(InputAgentState):
     custom_state: str
 
 
@@ -457,10 +469,10 @@ agent = create_agent(
 def test_injected_state_in_middleware_agent() -> None:
     """Test that custom state is properly injected into tools when using middleware."""
     result = agent.invoke(
-        {
-            "custom_state": "I love pizza",
-            "messages": [HumanMessage("Call the test state tool")],
-        }
+        _CustomInputState(
+            messages=[HumanMessage("Call the test state tool")],
+            custom_state="I love pizza",
+        )
     )
 
     messages = result["messages"]
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_tools.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_tools.py
index 7e008e720be..587345b1f15 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_tools.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_tools.py
@@ -13,6 +13,7 @@ from langchain.agents.factory import create_agent
 from langchain.agents.middleware.types import (
     AgentMiddleware,
     AgentState,
+    InputAgentState,
     ModelCallResult,
     ModelRequest,
     ModelResponse,
@@ -180,6 +181,9 @@ def test_middleware_can_add_and_remove_tools() -> None:
     class AdminState(AgentState[Any]):
         is_admin: bool
 
+    class AdminInputState(InputAgentState):
+        is_admin: bool
+
     class ConditionalToolMiddleware(AgentMiddleware[AdminState]):
         state_schema = AdminState
 
@@ -209,11 +213,11 @@ def test_middleware_can_add_and_remove_tools() -> None:
 
     # Test non-admin user - should not have access to admin_tool
     # We can't directly inspect the bound model, but we can verify the agent runs
-    result = agent.invoke({"messages": [HumanMessage("Hello")], "is_admin": False})
+    result = agent.invoke(AdminInputState(messages=[HumanMessage("Hello")], is_admin=False))
     assert "messages" in result
 
     # Test admin user - should have access to all tools
-    result = agent.invoke({"messages": [HumanMessage("Hello")], "is_admin": True})
+    result = agent.invoke(AdminInputState(messages=[HumanMessage("Hello")], is_admin=True))
     assert "messages" in result
 
 
@@ -383,8 +387,8 @@ def test_tool_node_not_accepted() -> None:
     tool_node = ToolNode([some_tool])
 
     with pytest.raises(TypeError, match="'ToolNode' object is not iterable"):
-        create_agent(
+        create_agent(  # type: ignore[call-overload]
             model=FakeToolCallingModel(),
-            tools=tool_node,  # type: ignore[arg-type]
+            tools=tool_node,
             system_prompt="You are a helpful assistant.",
         )
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_transformers.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_transformers.py
index c660b8bb13c..a4c2f0902c7 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_transformers.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_transformers.py
@@ -60,7 +60,7 @@ def test_middleware_transformer_registered_on_compiled_graph() -> None:
 
     run = agent.stream_events({"messages": [HumanMessage("hi")]}, version="v3")
 
-    assert "middleware_marker" in run._mux.extensions  # type: ignore[attr-defined]
+    assert "middleware_marker" in run._mux.extensions
     # Drain to close the run cleanly.
     list(run.tool_calls)
 
@@ -80,7 +80,7 @@ def test_middleware_and_user_transformers_compose_in_order() -> None:
 
     run = agent.stream_events({"messages": [HumanMessage("hi")]}, version="v3")
 
-    transformers = run._mux._transformers  # type: ignore[attr-defined]
+    transformers = run._mux._transformers
     tool_call_idx = next(
         i for i, t in enumerate(transformers) if isinstance(t, ToolCallTransformer)
     )
@@ -119,7 +119,7 @@ def test_transformers_from_multiple_middleware_preserve_middleware_order() -> No
 
     run = agent.stream_events({"messages": [HumanMessage("hi")]}, version="v3")
 
-    transformers = run._mux._transformers  # type: ignore[attr-defined]
+    transformers = run._mux._transformers
     idx_a = next(i for i, t in enumerate(transformers) if isinstance(t, _MarkerA))
     idx_b = next(i for i, t in enumerate(transformers) if isinstance(t, _MarkerB))
     assert idx_a < idx_b
@@ -136,7 +136,7 @@ def test_middleware_without_transformers_does_not_affect_registry() -> None:
     agent = create_agent(model=FakeToolCallingModel(), tools=[], middleware=[_Middleware()])
     run = agent.stream_events({"messages": [HumanMessage("hi")]}, version="v3")
 
-    transformers = run._mux._transformers  # type: ignore[attr-defined]
+    transformers = run._mux._transformers
     assert any(isinstance(t, ToolCallTransformer) for t in transformers)
     assert not any(isinstance(t, _MiddlewareMarker) for t in transformers)
 
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call.py
index 65fb57a90fd..1890038bdc1 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call.py
@@ -169,7 +169,7 @@ class TestRetryLogic:
             def __init__(self, max_retries: int = 3):
                 super().__init__()
                 self.max_retries = max_retries
-                self.attempts = []
+                self.attempts: list[int] = []
 
             def wrap_model_call(
                 self,
@@ -1195,7 +1195,7 @@ class TestWrapModelCallDecorator:
             messages: list[Any]
             custom_field: str
 
-        @wrap_model_call(state_schema=CustomState)
+        @wrap_model_call(state_schema=CustomState)  # type: ignore[type-var]
         def middleware_with_schema(
             request: ModelRequest,
             handler: Callable[[ModelRequest], ModelResponse],
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call_state_update.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call_state_update.py
index 4257f31e990..e24493bf821 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call_state_update.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call_state_update.py
@@ -153,7 +153,7 @@ class TestCustomStateField:
             summary: str
 
         class SummaryMiddleware(AgentMiddleware):
-            state_schema = MyState  # type: ignore[assignment]
+            state_schema = MyState
 
             def wrap_model_call(
                 self,
@@ -437,7 +437,7 @@ class TestComposition:
             custom_key: str
 
         class OuterMiddleware(AgentMiddleware):
-            state_schema = MyState  # type: ignore[assignment]
+            state_schema = MyState
 
             def wrap_model_call(
                 self,
@@ -456,7 +456,7 @@ class TestComposition:
                 )
 
         class InnerMiddleware(AgentMiddleware):
-            state_schema = MyState  # type: ignore[assignment]
+            state_schema = MyState
 
             def wrap_model_call(
                 self,
@@ -493,7 +493,7 @@ class TestComposition:
             outer_key: str
 
         class OuterMiddleware(AgentMiddleware):
-            state_schema = MyState  # type: ignore[assignment]
+            state_schema = MyState
 
             def wrap_model_call(
                 self,
@@ -507,7 +507,7 @@ class TestComposition:
                 )
 
         class InnerMiddleware(AgentMiddleware):
-            state_schema = MyState  # type: ignore[assignment]
+            state_schema = MyState
 
             def wrap_model_call(
                 self,
@@ -550,7 +550,7 @@ class TestComposition:
                 return handler(request)
 
         class InnerMiddleware(AgentMiddleware):
-            state_schema = MyState  # type: ignore[assignment]
+            state_schema = MyState
 
             def wrap_model_call(
                 self,
@@ -752,7 +752,7 @@ class TestAsyncComposition:
                 return await handler(request)
 
         class InnerMiddleware(AgentMiddleware):
-            state_schema = MyState  # type: ignore[assignment]
+            state_schema = MyState
 
             async def awrap_model_call(
                 self,
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_context_editing.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_context_editing.py
index 39f79ac7452..0220e078ce5 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_context_editing.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_context_editing.py
@@ -37,14 +37,14 @@ class _TokenCountingChatModel(FakeChatModel):
     def get_num_tokens_from_messages(
         self,
         messages: list[BaseMessage],
-        tools: Sequence | None = None,
+        tools: Sequence[Any] | None = None,
     ) -> int:
         return sum(_count_message_tokens(message) for message in messages)
 
 
 def _count_message_tokens(message: MessageLikeRepresentation) -> int:
     if isinstance(message, (AIMessage, ToolMessage)):
-        return _count_content(message.content)
+        return _count_content(cast("MessageLikeRepresentation", message.content))
     if isinstance(message, str):
         return len(message)
     return len(str(message))
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_model_call_limit.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_model_call_limit.py
index 05ac31d6abe..dc444f8a208 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_model_call_limit.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_model_call_limit.py
@@ -1,3 +1,5 @@
+from typing import TYPE_CHECKING
+
 import pytest
 from langchain_core.messages import AIMessage, HumanMessage, ToolMessage
 from langchain_core.tools import tool
@@ -5,6 +7,7 @@ from langgraph.checkpoint.memory import InMemorySaver
 from langgraph.runtime import Runtime
 
 from langchain.agents.factory import create_agent
+from langchain.agents.middleware import InputAgentState
 from langchain.agents.middleware.model_call_limit import (
     ModelCallLimitExceededError,
     ModelCallLimitMiddleware,
@@ -12,6 +15,9 @@ from langchain.agents.middleware.model_call_limit import (
 )
 from tests.unit_tests.agents.model import FakeToolCallingModel
 
+if TYPE_CHECKING:
+    from langchain_core.runnables import RunnableConfig
+
 
 @tool
 def simple_tool(value: str) -> str:
@@ -215,13 +221,13 @@ def test_run_limit_resets_between_invocations() -> None:
 
     agent = create_agent(model=model, middleware=[middleware], checkpointer=InMemorySaver())
 
-    thread_config = {"configurable": {"thread_id": "test_thread"}}
-    agent.invoke({"messages": [HumanMessage("Hello")]}, thread_config)
-    agent.invoke({"messages": [HumanMessage("Hello again")]}, thread_config)
-    agent.invoke({"messages": [HumanMessage("Hello third")]}, thread_config)
+    thread_config: RunnableConfig = {"configurable": {"thread_id": "test_thread"}}
+    agent.invoke(InputAgentState(messages=[HumanMessage("Hello")]), thread_config)
+    agent.invoke(InputAgentState(messages=[HumanMessage("Hello again")]), thread_config)
+    agent.invoke(InputAgentState(messages=[HumanMessage("Hello third")]), thread_config)
 
     # Fourth run: should raise, thread_model_call_count == 3 (limit)
     with pytest.raises(ModelCallLimitExceededError) as exc_info:
-        agent.invoke({"messages": [HumanMessage("Hello fourth")]}, thread_config)
+        agent.invoke(InputAgentState(messages=[HumanMessage("Hello fourth")]), thread_config)
     error_msg = str(exc_info.value)
     assert "thread limit (3/3)" in error_msg
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_pii.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_pii.py
index acac3cfc444..1f7f2162f74 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_pii.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_pii.py
@@ -15,6 +15,7 @@ from langchain_core.messages import (
 )
 from langchain_core.tools import tool
 from langgraph.runtime import Runtime
+from langgraph.stream._types import ProtocolEvent
 from langgraph.stream.transformers import MessagesTransformer
 
 from langchain.agents import AgentState
@@ -578,7 +579,7 @@ class TestCustomDetector:
         KeyError: 'value' when used with hash or mask strategies.
         """
 
-        def detect_phone(content: str) -> list[dict]:  # type: ignore[type-arg]
+        def detect_phone(content: str) -> list[dict[str, Any]]:
             return [
                 {"text": m.group(), "start": m.start(), "end": m.end()}
                 for m in re.finditer(r"\+91[\s.-]?\d{10}", content)
@@ -586,7 +587,7 @@ class TestCustomDetector:
 
         middleware = PIIMiddleware(
             "indian_phone",
-            detector=detect_phone,
+            detector=detect_phone,  # type: ignore[arg-type]
             strategy="hash",
             apply_to_input=True,
         )
@@ -601,7 +602,7 @@ class TestCustomDetector:
     def test_custom_callable_detector_with_text_key_mask(self) -> None:
         """Custom detectors returning 'text' instead of 'value' must work with mask strategy."""
 
-        def detect_phone(content: str) -> list[dict]:  # type: ignore[type-arg]
+        def detect_phone(content: str) -> list[dict[str, Any]]:
             return [
                 {"text": m.group(), "start": m.start(), "end": m.end()}
                 for m in re.finditer(r"\+91[\s.-]?\d{10}", content)
@@ -609,7 +610,7 @@ class TestCustomDetector:
 
         middleware = PIIMiddleware(
             "indian_phone",
-            detector=detect_phone,
+            detector=detect_phone,  # type: ignore[arg-type]
             strategy="mask",
             apply_to_input=True,
         )
@@ -715,7 +716,7 @@ class TestMultipleMiddleware:
 # ============================================================================
 
 
-def _make_delta_event(text: str, *, index: int = 0, run_id: str = "r1") -> dict[str, Any]:
+def _make_delta_event(text: str, *, index: int = 0, run_id: str = "r1") -> ProtocolEvent:
     """Build a `messages` protocol event for a text content-block delta."""
     return {
         "type": "event",
@@ -735,7 +736,7 @@ def _make_delta_event(text: str, *, index: int = 0, run_id: str = "r1") -> dict[
     }
 
 
-def _make_finish_event(text: str, *, index: int = 0, run_id: str = "r1") -> dict[str, Any]:
+def _make_finish_event(text: str, *, index: int = 0, run_id: str = "r1") -> ProtocolEvent:
     """Build a `messages` protocol event for content-block-finish on a text block."""
     return {
         "type": "event",
@@ -755,7 +756,7 @@ def _make_finish_event(text: str, *, index: int = 0, run_id: str = "r1") -> dict
     }
 
 
-def _emitted_text(events: list[dict[str, Any]]) -> str:
+def _emitted_text(events: list[ProtocolEvent]) -> tuple[str, dict[int, str]]:
     """Concatenate delta + finalized text the way a streaming consumer would."""
     parts = []
     final_by_index: dict[int, str] = {}
@@ -772,10 +773,10 @@ def _emitted_text(events: list[dict[str, Any]]) -> str:
                 final_by_index[payload["index"]] = content["text"]
     # Concatenated delta stream is what the consumer sees in real time;
     # finalized text is the snapshot. Return both via a tuple-like dict.
-    return "".join(parts), final_by_index  # type: ignore[return-value]
+    return "".join(parts), final_by_index
 
 
-def _run_transformer(transformer: Any, events: list[dict[str, Any]]) -> list[dict[str, Any]]:
+def _run_transformer(transformer: Any, events: list[ProtocolEvent]) -> list[ProtocolEvent]:
     """Feed events through the transformer (mutates in place) and return them."""
     for event in events:
         transformer.process(event)
@@ -840,6 +841,7 @@ class TestPIIStreamTransformer:
         redacted = transformer._redact_value(msg)
 
         # Original untouched.
+        assert isinstance(msg.content[0], dict)
         assert msg.content[0]["text"] == "Reach me at alice@example.com"
         # Redacted copy walked every block.
         assert "alice@example.com" not in redacted.content[0]["text"]
@@ -898,7 +900,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule, lookback=32)
 
-        events = [
+        events: list[ProtocolEvent] = [
             {
                 "type": "event",
                 "method": "messages",
@@ -953,7 +955,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email", strategy="block").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "messages",
             "params": {
@@ -986,7 +988,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)  # default lookback=128
 
-        events = [
+        events: list[ProtocolEvent] = [
             {
                 "type": "event",
                 "method": "messages",
@@ -1031,7 +1033,7 @@ class TestPIIStreamTransformer:
 
         # 50-char args with PII near the start; emit_end = 50 - 8 = 42.
         args = '{"to": "alice@example.com", "subject": "hi"}'
-        events = [
+        events: list[ProtocolEvent] = [
             {
                 "type": "event",
                 "method": "messages",
@@ -1082,7 +1084,7 @@ class TestPIIStreamTransformer:
             '{"to": "alice@example',
             '{"to": "alice@example.com"}',
         ]
-        events = [
+        events: list[ProtocolEvent] = [
             {
                 "type": "event",
                 "method": "messages",
@@ -1124,7 +1126,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        events = [
+        events: list[ProtocolEvent] = [
             {
                 "type": "event",
                 "method": "messages",
@@ -1156,7 +1158,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email", strategy="block").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "messages",
             "params": {
@@ -1192,7 +1194,7 @@ class TestPIIStreamTransformer:
             ],
             id="m1",
         )
-        event: dict[str, Any] = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "messages",
             "params": {
@@ -1217,7 +1219,7 @@ class TestPIIStreamTransformer:
             ],
             id="m1",
         )
-        event: dict[str, Any] = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "messages",
             "params": {
@@ -1235,7 +1237,7 @@ class TestPIIStreamTransformer:
         transformer = _PIIStreamTransformer(rule=rule)
 
         msg = ToolMessage(content="Result: alice@example.com", tool_call_id="c1", id="m1")
-        event: dict[str, Any] = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "messages",
             "params": {
@@ -1258,7 +1260,7 @@ class TestPIIStreamTransformer:
         """Tools events route to the new handler without error."""
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "tools",
             "params": {
@@ -1279,7 +1281,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "tools",
             "params": {
@@ -1303,7 +1305,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "tools",
             "params": {
@@ -1365,7 +1367,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        events = [
+        events: list[ProtocolEvent] = [
             {
                 "type": "event",
                 "method": "messages",
@@ -1403,6 +1405,7 @@ class TestPIIStreamTransformer:
             content="",
             invalid_tool_calls=[
                 InvalidToolCall(
+                    type="invalid_tool_call",
                     name="send_email",
                     args='{"to": "alice@example.com"} BROKEN',
                     id="c1",
@@ -1411,16 +1414,18 @@ class TestPIIStreamTransformer:
             ],
             id="m1",
         )
-        redacted = transformer._redact_value(msg)
+        redacted: AIMessage = transformer._redact_value(msg)
+        assert redacted.invalid_tool_calls[0]["args"] is not None
         assert "alice@example.com" not in redacted.invalid_tool_calls[0]["args"]
         assert "[REDACTED_EMAIL]" in redacted.invalid_tool_calls[0]["args"]
+        assert msg.invalid_tool_calls[0]["args"] is not None
         assert "alice@example.com" in msg.invalid_tool_calls[0]["args"]
 
     def test_tool_started_input_is_redacted(self) -> None:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "tools",
             "params": {
@@ -1445,7 +1450,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule, lookback=64)
 
-        events = [
+        events: list[ProtocolEvent] = [
             {
                 "type": "event",
                 "method": "tools",
@@ -1483,7 +1488,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "tools",
             "params": {
@@ -1506,7 +1511,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "tools",
             "params": {
@@ -1529,7 +1534,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "tools",
             "params": {
@@ -1551,7 +1556,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule, lookback=64)
 
-        delta_event = {
+        delta_event: ProtocolEvent = {
             "type": "event",
             "method": "tools",
             "params": {
@@ -1567,7 +1572,7 @@ class TestPIIStreamTransformer:
         transformer.process(delta_event)
         assert "c1" in transformer._tool_buffers
 
-        finish_event = {
+        finish_event: ProtocolEvent = {
             "type": "event",
             "method": "tools",
             "params": {
@@ -1588,7 +1593,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email", strategy="block").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "tools",
             "params": {
@@ -1609,7 +1614,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email", strategy="block").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        event = {
+        event: ProtocolEvent = {
             "type": "event",
             "method": "messages",
             "params": {
@@ -1646,7 +1651,7 @@ class TestPIIStreamTransformer:
             _make_finish_event("Reach me at alice@example.com tomorrow."),
         ]
         _run_transformer(transformer, events)
-        streamed, finals = _emitted_text(events)  # type: ignore[misc]
+        streamed, finals = _emitted_text(events)
 
         # The raw email never reaches the wire — the delta is held in the
         # lookback buffer and the finalize snapshot is the redacted text.
@@ -1665,7 +1670,7 @@ class TestPIIStreamTransformer:
             _make_finish_event("Hi, contact alice@example.com when ready"),
         ]
         _run_transformer(transformer, events)
-        streamed, finals = _emitted_text(events)  # type: ignore[misc]
+        streamed, finals = _emitted_text(events)
 
         # The held-buffer should have prevented the raw email from being
         # released until detection ran over the concatenation.
@@ -1695,7 +1700,7 @@ class TestPIIStreamTransformer:
             _make_finish_event(text),
         ]
         _run_transformer(transformer, events)
-        streamed, finals = _emitted_text(events)  # type: ignore[misc]
+        streamed, finals = _emitted_text(events)
 
         # No prefix of the email reaches the wire.
         assert email not in streamed
@@ -1716,7 +1721,7 @@ class TestPIIStreamTransformer:
             _make_finish_event("Card: 5425 2334 3010 9903 next"),
         ]
         _run_transformer(transformer, events)
-        streamed, finals = _emitted_text(events)  # type: ignore[misc]
+        streamed, finals = _emitted_text(events)
 
         # No prefix of the card may reach the wire — the lookback buffer
         # holds whitespace-separated groups until detection runs over the
@@ -1762,7 +1767,7 @@ class TestPIIStreamTransformer:
         transformer.process(clean_event)  # no raise yet
 
         # Second delta completes the email — detection fires, raises.
-        completing_event = _make_delta_event("@example.com soon")
+        completing_event: ProtocolEvent = _make_delta_event("@example.com soon")
         with pytest.raises(PIIDetectionError):
             transformer.process(completing_event)
 
@@ -1777,7 +1782,7 @@ class TestPIIStreamTransformer:
             _make_finish_event("Hello there, how are you?"),
         ]
         _run_transformer(transformer, events)
-        streamed, finals = _emitted_text(events)  # type: ignore[misc]
+        streamed, finals = _emitted_text(events)
 
         # Deltas hold everything back; the finalize event carries the
         # whole block at once. `ChatModelStream._resolve_block_text`
@@ -1801,7 +1806,7 @@ class TestPIIStreamTransformer:
             _make_finish_event("alice@example.com"),
         ]
         _run_transformer(transformer, events)
-        _, finals = _emitted_text(events)  # type: ignore[misc]
+        _, finals = _emitted_text(events)
 
         assert "alice@example.com" not in finals[0]
         assert "[REDACTED_EMAIL]" in finals[0]
@@ -1851,7 +1856,7 @@ class TestPIIStreamTransformer:
         assert ("r1", 0) in transformer._buffers
 
         # message-finish for the run wipes any (run-id, *) entries.
-        message_finish_event = {
+        message_finish_event: ProtocolEvent = {
             "type": "event",
             "method": "messages",
             "params": {
@@ -1886,7 +1891,7 @@ class TestPIIStreamTransformer:
             _make_finish_event("hello alice@example.com goodbye"),
         ]
         _run_transformer(transformer, events)
-        _, finals = _emitted_text(events)  # type: ignore[misc]
+        _, finals = _emitted_text(events)
         # The finalized snapshot always re-runs detection over the full text.
         assert "alice@example.com" not in finals[0]
 
@@ -1901,7 +1906,7 @@ class TestPIIStreamTransformer:
         rule = RedactionRule(pii_type="email").resolve()
         transformer = _PIIStreamTransformer(rule=rule)
 
-        data_event = {
+        data_event: ProtocolEvent = {
             "type": "event",
             "method": "messages",
             "params": {
@@ -1934,7 +1939,7 @@ class TestPIIStreamTransformer:
         agent = create_agent(model, [], middleware=[PIIMiddleware("email", apply_to_output=True)])
 
         run = agent.stream_events({"messages": [HumanMessage("hi")]}, version="v3")
-        transformers = run._mux._transformers  # type: ignore[attr-defined]
+        transformers = run._mux._transformers
 
         pii_idx = next(
             i for i, t in enumerate(transformers) if isinstance(t, _PIIStreamTransformer)
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_summarization.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_summarization.py
index 460bf513f8b..21d62fba241 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_summarization.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_summarization.py
@@ -30,7 +30,9 @@ from typing_extensions import override
 
 from langchain.agents import AgentState
 from langchain.agents.middleware.summarization import (
+    ContextSize,
     SummarizationMiddleware,
+    TriggerClause,
     _provider_matches,
 )
 from langchain.chat_models import init_chat_model
@@ -1153,8 +1155,8 @@ def test_summarization_middleware_cutoff_at_start_of_tool_sequence() -> None:
 def test_trigger_copies_mutable_inputs() -> None:
     """Test caller mutations do not change stored trigger configuration."""
     model = FakeToolCallingModel()
-    clause = {"tokens": 1000}
-    trigger = [clause]
+    clause: TriggerClause = {"tokens": 1000}
+    trigger: list[ContextSize | TriggerClause] = [clause]
 
     middleware = SummarizationMiddleware(
         model=model,
@@ -1171,7 +1173,7 @@ def test_trigger_copies_mutable_inputs() -> None:
         return 500
 
     middleware.token_counter = token_counter_low
-    state = {"messages": [HumanMessage(content="1"), HumanMessage(content="2")]}
+    state = AgentState(messages=[HumanMessage(content="1"), HumanMessage(content="2")])
     result = middleware.before_model(state, Runtime())
     assert result is None
 
@@ -1231,13 +1233,13 @@ def test_and_trigger_conditions() -> None:
         return 1500  # Above token threshold
 
     middleware.token_counter = token_counter_high
-    state = {
-        "messages": [
+    state = AgentState(
+        messages=[
             HumanMessage(content="1"),
             AIMessage(content="2"),
             HumanMessage(content="3"),
         ]
-    }
+    )
     result = middleware.before_model(state, Runtime())
     assert result is None, "Should not summarize when only tokens condition is met"
 
@@ -1247,8 +1249,8 @@ def test_and_trigger_conditions() -> None:
         return 500  # Below token threshold
 
     middleware.token_counter = token_counter_low
-    state = {
-        "messages": [
+    state = AgentState(
+        messages=[
             HumanMessage(content="1"),
             AIMessage(content="2"),
             HumanMessage(content="3"),
@@ -1256,7 +1258,7 @@ def test_and_trigger_conditions() -> None:
             HumanMessage(content="5"),
             AIMessage(content="6"),
         ]
-    }
+    )
     result = middleware.before_model(state, Runtime())
     assert result is None, "Should not summarize when only messages condition is met"
 
@@ -1289,14 +1291,14 @@ def test_or_trigger_conditions_with_and_clauses() -> None:
         return 5500
 
     middleware.token_counter = token_counter_5500
-    state = {
-        "messages": [
+    state = AgentState(
+        messages=[
             HumanMessage(content="1"),
             AIMessage(content="2"),
             HumanMessage(content="3"),
             AIMessage(content="4"),
         ]
-    }
+    )
     result = middleware.before_model(state, Runtime())
     assert result is not None, "Should summarize when first OR clause is met"
 
@@ -1306,7 +1308,7 @@ def test_or_trigger_conditions_with_and_clauses() -> None:
         return 3500
 
     middleware.token_counter = token_counter_3500
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(7)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(7)])
     result = middleware.before_model(state, Runtime())
     assert result is not None, "Should summarize when second OR clause is met"
 
@@ -1318,14 +1320,14 @@ def test_or_trigger_conditions_with_and_clauses() -> None:
         return 4500
 
     middleware.token_counter = token_counter_4500
-    state = {
-        "messages": [
+    state = AgentState(
+        messages=[
             HumanMessage(content="1"),
             AIMessage(content="2"),
             HumanMessage(content="3"),
             AIMessage(content="4"),
         ]
-    }
+    )
     result = middleware.before_model(state, Runtime())
     assert result is None, "Should not summarize when no complete clause is met"
 
@@ -1337,7 +1339,7 @@ async def test_and_trigger_conditions_async() -> None:
         trigger={"tokens": 1000, "messages": 5},
         keep=("messages", 2),
     )
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(6)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(6)])
 
     # Only the messages threshold met (tokens below) -> should not summarize.
     def token_counter_low(_messages: Iterable[MessageLikeRepresentation]) -> int:
@@ -1367,7 +1369,7 @@ async def test_or_trigger_conditions_with_and_clauses_async() -> None:
         ],
         keep=("messages", 2),
     )
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(4)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(4)])
 
     # First clause met (tokens = 5500, messages = 4) -> should summarize.
     def token_counter_5500(_messages: Iterable[MessageLikeRepresentation]) -> int:
@@ -1401,7 +1403,7 @@ def test_backward_compatibility_tuple_trigger() -> None:
         return 1500
 
     middleware_single.token_counter = token_counter_high
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(3)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(3)])
     result = middleware_single.before_model(state, Runtime())
     assert result is not None, "Single tuple trigger should work"
 
@@ -1414,7 +1416,7 @@ def test_backward_compatibility_tuple_trigger() -> None:
 
     # Should trigger with high tokens (first condition met)
     middleware_list.token_counter = token_counter_high
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(3)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(3)])
     result = middleware_list.before_model(state, Runtime())
     assert result is not None, "List of tuples should trigger when any condition met"
 
@@ -1423,7 +1425,7 @@ def test_backward_compatibility_tuple_trigger() -> None:
         return 100
 
     middleware_list.token_counter = token_counter_low
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(6)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(6)])
     result = middleware_list.before_model(state, Runtime())
     assert result is not None, "List of tuples should trigger when second condition met"
 
@@ -1447,7 +1449,7 @@ def test_mixed_and_or_conditions() -> None:
         return 4500
 
     middleware.token_counter = token_counter_high
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(12)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(12)])
     result = middleware.before_model(state, Runtime())
     assert result is not None, "Should trigger when AND clause is met"
 
@@ -1456,13 +1458,13 @@ def test_mixed_and_or_conditions() -> None:
         return 1000
 
     middleware.token_counter = token_counter_low
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(55)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(55)])
     result = middleware.before_model(state, Runtime())
     assert result is not None, "Should trigger when simple messages condition is met"
 
     # Test case 3: Neither condition met
     middleware.token_counter = token_counter_low
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(8)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(8)])
     result = middleware.before_model(state, Runtime())
     assert result is None, "Should not trigger when no condition is met"
 
@@ -1484,21 +1486,21 @@ def test_fraction_in_and_trigger() -> None:
     # Test case 1: Both conditions met
     # 5 messages * 200 = 1000 tokens (profile max is 1000)
     # 1000 / 1000 = 1.0 >= 0.8  AND messages = 5 >= 5
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(5)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(5)])
     result = middleware.before_model(state, Runtime())
     assert result is not None, "Should trigger when both fraction and messages conditions met"
 
     # Test case 2: Only messages condition met
     # 3 messages * 200 = 600 tokens
     # 600 / 1000 = 0.6 < 0.8 and messages = 3 < 5
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(3)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(3)])
     result = middleware.before_model(state, Runtime())
     assert result is None, "Should not trigger when neither condition is fully met"
 
     # Test case 3: High fraction but not enough messages
     # 4 messages * 200 = 800 tokens
     # 800 / 1000 = 0.8 >= 0.8 but messages = 4 < 5
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(4)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(4)])
     result = middleware.before_model(state, Runtime())
     assert result is None, "Should not trigger when only fraction condition is met"
 
@@ -1511,7 +1513,7 @@ def test_trigger_validation_errors() -> None:
     with pytest.raises(ValueError, match="Unsupported trigger metric"):
         SummarizationMiddleware(
             model=model,
-            trigger={"invalid_metric": 100},
+            trigger={"invalid_metric": 100},  # type: ignore[arg-type]
         )
 
     # Invalid fraction value (> 1) — shares the tuple path's message via
@@ -1547,21 +1549,21 @@ def test_trigger_validation_errors() -> None:
     with pytest.raises(ValueError, match="Fraction trigger values must be numeric"):
         SummarizationMiddleware(
             model=model,
-            trigger={"fraction": "invalid"},
+            trigger={"fraction": "invalid"},  # type: ignore[arg-type]
         )
 
     # Float value for an integer metric is rejected (no silent truncation)
     with pytest.raises(ValueError, match="tokens trigger values must be integers"):
         SummarizationMiddleware(
             model=model,
-            trigger={"tokens": 1000.5},
+            trigger={"tokens": 1000.5},  # type: ignore[arg-type]
         )
 
     # Numeric string for an integer metric is rejected (no silent coercion)
     with pytest.raises(ValueError, match="messages trigger values must be integers"):
         SummarizationMiddleware(
             model=model,
-            trigger={"messages": "10"},
+            trigger={"messages": "10"},  # type: ignore[arg-type]
         )
 
     # Boolean is rejected (bool is an int subclass)
@@ -1575,7 +1577,7 @@ def test_trigger_validation_errors() -> None:
     with pytest.raises(TypeError, match="Unsupported trigger item type"):
         SummarizationMiddleware(
             model=model,
-            trigger=["invalid"],
+            trigger=["invalid"],  # type: ignore[list-item]
         )
 
     # Unsupported top-level trigger type (not a tuple, dict, or list)
@@ -1616,7 +1618,7 @@ def test_empty_list_trigger_never_summarizes() -> None:
         token_counter=lambda _: 10_000,
     )
     assert middleware._trigger_conditions == []
-    state = {"messages": [HumanMessage(content=str(i)) for i in range(50)]}
+    state = AgentState(messages=[HumanMessage(content=str(i)) for i in range(50)])
     assert middleware.before_model(state, Runtime()) is None
 
 
diff --git a/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_tool_call_limit.py b/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_tool_call_limit.py
index ade644a3788..9050eb6751e 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_tool_call_limit.py
+++ b/libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_tool_call_limit.py
@@ -7,6 +7,7 @@ from langgraph.checkpoint.memory import InMemorySaver
 
 from langchain.agents.factory import create_agent
 from langchain.agents.middleware.tool_call_limit import (
+    ExitBehavior,
     ToolCallLimitExceededError,
     ToolCallLimitMiddleware,
     ToolCallLimitState,
@@ -34,7 +35,8 @@ def test_middleware_initialization_validation() -> None:
     assert middleware.run_limit is None
 
     # Test exit behaviors
-    for behavior in ["error", "end", "continue"]:
+    behaviors: tuple[ExitBehavior, ...] = ("error", "end", "continue")
+    for behavior in behaviors:
         middleware = ToolCallLimitMiddleware(thread_limit=5, exit_behavior=behavior)
         assert middleware.exit_behavior == behavior