x

libs/core/tests/unit_tests/test_tools.py

@@ -2,6 +2,11 @@
 
 import inspect
 import json
+from langchain_core.tools import tool
+from typing import Annotated, get_type_hints
+import inspect
+
+
 import sys
 import textwrap
 import threading
@@ -1737,6 +1742,8 @@ def test__is_message_content_block(obj: Any, expected: bool) -> None:
     assert _is_message_content_block(obj) is expected
 
 
+
+
 @pytest.mark.parametrize(
     ("obj", "expected"),
     [
@@ -1871,6 +1878,22 @@ class ModelD(ModelC, Generic[D]):
     assert actual == expected
 
 
+def test_tool_annotations_preserved() -> None:
+    """Test that annotations are preserved when creating a tool."""
+    @tool
+    def my_tool(val: int, other_val: Annotated[dict, "my annotation"]) -> str:
+        """Tool docstring."""
+        return other_val
+
+    schema = my_tool.get_input_schema()
+
+    expected_type_hints = {
+        name: hint
+        for name, hint in my_tool.func.__annotations__.items()
+        if name in inspect.signature(my_tool.func).parameters
+    }
+    assert schema.__annotations__ == expected_type_hints
+
 @pytest.mark.skipif(PYDANTIC_MAJOR_VERSION != 2, reason="Testing pydantic v2.")
 def test_tool_args_schema_pydantic_v2_with_metadata() -> None:
     from pydantic import BaseModel as BaseModelV2