From 87d432e1c7fb1dadff24e2742d8b8cf52816fc9f Mon Sep 17 00:00:00 2001
From: Sydney Runkle <sydneymarierunkle@gmail.com>
Date: Thu, 13 Nov 2025 10:01:44 -0500
Subject: [PATCH] Revert changes to keep only chat_agent_executor modifications

---
 .../langgraph/_internal/_runnable.py          |  7 +---
 libs/prebuilt/langgraph/prebuilt/tool_node.py |  5 ++-
 libs/prebuilt/tests/test_tool_node.py         | 34 ++++++++++---------
 3 files changed, 21 insertions(+), 25 deletions(-)

diff --git a/libs/langgraph/langgraph/_internal/_runnable.py b/libs/langgraph/langgraph/_internal/_runnable.py
index 0e51c4286..63e03f544 100644
--- a/libs/langgraph/langgraph/_internal/_runnable.py
+++ b/libs/langgraph/langgraph/_internal/_runnable.py
@@ -316,12 +316,7 @@ class RunnableCallable(Runnable):
                 continue
 
             # If the kwarg is accepted by the function, store the key / runtime attribute to inject
-            # Use the actual parameter default from the function signature if available,
-            # otherwise fall back to the default from KWARGS_CONFIG_KEYS
-            param_default = (
-                p.default if p.default is not inspect.Parameter.empty else default
-            )
-            self.func_accepts[kw] = (runtime_key, param_default)
+            self.func_accepts[kw] = (runtime_key, default)
 
     def __repr__(self) -> str:
         repr_args = {
diff --git a/libs/prebuilt/langgraph/prebuilt/tool_node.py b/libs/prebuilt/langgraph/prebuilt/tool_node.py
index a42e5ea70..c287743dd 100644
--- a/libs/prebuilt/langgraph/prebuilt/tool_node.py
+++ b/libs/prebuilt/langgraph/prebuilt/tool_node.py
@@ -84,7 +84,6 @@ from langchain_core.tools.base import (
 from langgraph._internal._runnable import RunnableCallable
 from langgraph.errors import GraphBubbleUp
 from langgraph.graph.message import REMOVE_ALL_MESSAGES
-from langgraph.runtime import DEFAULT_RUNTIME
 from langgraph.store.base import BaseStore  # noqa: TC002
 from langgraph.types import Command, Send, StreamWriter
 from pydantic import BaseModel, ValidationError
@@ -703,7 +702,7 @@ class ToolNode(RunnableCallable):
         self,
         input: list[AnyMessage] | dict[str, Any] | BaseModel,
         config: RunnableConfig,
-        runtime: Runtime = DEFAULT_RUNTIME,
+        runtime: Runtime,
     ) -> Any:
         tool_calls, input_type = self._parse_input(input)
         config_list = get_config_list(config, len(tool_calls))
@@ -735,7 +734,7 @@ class ToolNode(RunnableCallable):
         self,
         input: list[AnyMessage] | dict[str, Any] | BaseModel,
         config: RunnableConfig,
-        runtime: Runtime = DEFAULT_RUNTIME,
+        runtime: Runtime,
     ) -> Any:
         tool_calls, input_type = self._parse_input(input)
         config_list = get_config_list(config, len(tool_calls))
diff --git a/libs/prebuilt/tests/test_tool_node.py b/libs/prebuilt/tests/test_tool_node.py
index 60a0c8ea8..a97bd1565 100644
--- a/libs/prebuilt/tests/test_tool_node.py
+++ b/libs/prebuilt/tests/test_tool_node.py
@@ -9,6 +9,7 @@ from typing import (
     NoReturn,
     TypeVar,
 )
+from unittest.mock import Mock
 
 import pytest
 from langchain_core.messages import (
@@ -50,26 +51,27 @@ from .model import FakeToolCallingModel
 pytestmark = pytest.mark.anyio
 
 
+def _create_mock_runtime(store: BaseStore | None = None) -> Mock:
+    """Create a mock Runtime object for testing ToolNode outside of graph context.
+
+    This helper is needed because ToolNode._func expects a Runtime parameter
+    which is injected by RunnableCallable from config["configurable"]["__pregel_runtime"].
+    When testing ToolNode directly (outside a graph), we need to provide this manually.
+    """
+    mock_runtime = Mock()
+    mock_runtime.store = store
+    mock_runtime.context = None
+    mock_runtime.stream_writer = lambda *args, **kwargs: None
+    return mock_runtime
+
+
 def _create_config_with_runtime(store: BaseStore | None = None) -> RunnableConfig:
-    """Create a RunnableConfig for testing ToolNode.
-
-    Since ToolNode now has a default Runtime, this helper can be simplified.
-    It only needs to inject a store if one is provided, otherwise an empty config works.
-
-    Args:
-        store: Optional store to inject via runtime. If None, no runtime is needed.
+    """Create a RunnableConfig with mock Runtime for testing ToolNode.
 
     Returns:
-        RunnableConfig, optionally with __pregel_runtime if store is provided.
+        RunnableConfig with __pregel_runtime in configurable dict.
     """
-    if store is None:
-        # No runtime needed - ToolNode will use DEFAULT_RUNTIME
-        return {}
-
-    # Create a mock runtime only when we need to inject a store
-    from langgraph.runtime import Runtime
-    runtime = Runtime(context=None, store=store, stream_writer=lambda *args, **kwargs: None)
-    return {"configurable": {"__pregel_runtime": runtime}}
+    return {"configurable": {"__pregel_runtime": _create_mock_runtime(store)}}
 
 
 def tool1(some_val: int, some_other_val: str) -> str: