From 58dd69f7f26fa967e438857f2f687b17e3e7dbe4 Mon Sep 17 00:00:00 2001
From: ccurme <chester.curme@gmail.com>
Date: Thu, 25 Jul 2024 12:46:36 -0400
Subject: [PATCH] core[patch]: fix mutating tool calls (#24677)

In some cases tool calls are mutated when passed through a tool.
---
 libs/core/langchain_core/tools.py        |  6 ++++--
 libs/core/tests/unit_tests/test_tools.py | 10 ++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/libs/core/langchain_core/tools.py b/libs/core/langchain_core/tools.py
index 85db1d3b92e..633faa7b343 100644
--- a/libs/core/langchain_core/tools.py
+++ b/libs/core/langchain_core/tools.py
@@ -20,6 +20,7 @@ tool for the job.
 from __future__ import annotations
 
 import asyncio
+import copy
 import functools
 import inspect
 import json
@@ -1481,8 +1482,9 @@ def _prep_run_args(
 ) -> Tuple[Union[str, Dict], Dict]:
     config = ensure_config(config)
     if _is_tool_call(input):
-        tool_call_id: Optional[str] = cast(ToolCall, input)["id"]
-        tool_input: Union[str, dict] = cast(ToolCall, input)["args"]
+        input_copy = copy.deepcopy(input)
+        tool_call_id: Optional[str] = cast(ToolCall, input_copy)["id"]
+        tool_input: Union[str, dict] = cast(ToolCall, input_copy)["args"]
     else:
         tool_call_id = None
         tool_input = cast(Union[str, dict], input)
diff --git a/libs/core/tests/unit_tests/test_tools.py b/libs/core/tests/unit_tests/test_tools.py
index 7f0fccbd050..489feeb7dca 100644
--- a/libs/core/tests/unit_tests/test_tools.py
+++ b/libs/core/tests/unit_tests/test_tools.py
@@ -977,6 +977,16 @@ class AFooBase(FooBase):
 def test_tool_pass_config(tool: BaseTool) -> None:
     assert tool.invoke({"bar": "baz"}, {"configurable": {"foo": "not-bar"}}) == "baz"
 
+    # Test tool calls
+    tool_call = {
+        "name": tool.name,
+        "args": {"bar": "baz"},
+        "id": "abc123",
+        "type": "tool_call",
+    }
+    _ = tool.invoke(tool_call, {"configurable": {"foo": "not-bar"}})
+    assert tool_call["args"] == {"bar": "baz"}
+
 
 @pytest.mark.parametrize(
     "tool", [foo, afoo, simple_foo, asimple_foo, FooBase(), AFooBase()]