core[patch]: support handle_tool_error=(Exception, ...) tuple

libs/core/langchain_core/tools/base.py

@@ -19,8 +19,6 @@ from typing import (
     TypeVar,
     Union,
     cast,
-    get_args,
-    get_origin,
     get_type_hints,
 )
 
@@ -37,6 +35,7 @@ from pydantic import (
 from pydantic.v1 import BaseModel as BaseModelV1
 from pydantic.v1 import ValidationError as ValidationErrorV1
 from pydantic.v1 import validate_arguments as validate_arguments_v1
+from typing_extensions import get_args, get_origin
 
 from langchain_core._api import deprecated
 from langchain_core.callbacks import (
@@ -333,13 +332,13 @@ class BaseTool(RunnableSerializable[Union[str, dict, ToolCall], Any]):
             typehint_mandate = """
 class ChildTool(BaseTool):
     ...
-    args_schema: Type[BaseModel] = SchemaClass
+    args_schema: type[BaseModel] = SchemaClass
     ..."""
             name = cls.__name__
             msg = (
                 f"Tool definition for {name} must include valid type annotations"
                 f" for argument 'args_schema' to behave as expected.\n"
-                f"Expected annotation of 'Type[BaseModel]'"
+                f"Expected annotation of 'type[BaseModel]'"
                 f" but got '{args_schema_type}'.\n"
                 f"Expected class looks like:\n"
                 f"{typehint_mandate}"
@@ -399,9 +398,9 @@ class ChildTool(BaseTool):
     You can use these to eg identify a specific instance of a tool with its use case.
     """
 
-    handle_tool_error: Optional[Union[bool, str, Callable[[ToolException], str]]] = (
+    handle_tool_error: Union[
-        False
+        None, bool, str, Callable[..., str], tuple[type[Exception], ...]
-    )
+    ] = False
     """Handle the content of the ToolException thrown."""
 
     handle_validation_error: Optional[
@@ -668,21 +667,33 @@ class ChildTool(BaseTool):
             else:
                 content = response
             status = "success"
-        except (ValidationError, ValidationErrorV1) as e:
-            if not self.handle_validation_error:
-                error_to_raise = e
-            else:
-                content = _handle_validation_error(e, flag=self.handle_validation_error)
-            status = "error"
-        except ToolException as e:
-            if not self.handle_tool_error:
-                error_to_raise = e
-            else:
-                content = _handle_tool_error(e, flag=self.handle_tool_error)
-            status = "error"
         except (Exception, KeyboardInterrupt) as e:
-            error_to_raise = e
             status = "error"
+            # Validation error (args don't match pydantic schema)
+            if isinstance(e, (ValidationError, ValidationErrorV1)):
+                # Unhandled
+                if not self.handle_validation_error:
+                    error_to_raise = e
+                # Handled
+                else:
+                    content = _handle_validation_error(
+                        e, flag=self.handle_validation_error
+                    )
+            # Tool error (error raised at tool runtime)
+            else:
+                if isinstance(self.handle_tool_error, tuple):
+                    handled_types: tuple = self.handle_tool_error
+                elif callable(self.handle_tool_error):
+                    handled_types = _infer_handled_types(self.handle_tool_error)
+                else:
+                    handled_types = (ToolException,)
+
+                # Unhandled
+                if not self.handle_tool_error or not isinstance(e, handled_types):
+                    error_to_raise = e
+                # Handled
+                else:
+                    content = _handle_tool_error(e, flag=self.handle_tool_error)
 
         if error_to_raise:
             run_manager.on_tool_error(error_to_raise)
@@ -785,21 +796,32 @@ class ChildTool(BaseTool):
             else:
                 content = response
             status = "success"
-        except ValidationError as e:
-            if not self.handle_validation_error:
-                error_to_raise = e
-            else:
-                content = _handle_validation_error(e, flag=self.handle_validation_error)
-            status = "error"
-        except ToolException as e:
-            if not self.handle_tool_error:
-                error_to_raise = e
-            else:
-                content = _handle_tool_error(e, flag=self.handle_tool_error)
-            status = "error"
         except (Exception, KeyboardInterrupt) as e:
-            error_to_raise = e
             status = "error"
+            # Validation error (args don't match pydantic schema)
+            if isinstance(e, (ValidationError, ValidationErrorV1)):
+                # Unhandled
+                if not self.handle_validation_error:
+                    error_to_raise = e
+                # Handled
+                else:
+                    content = _handle_validation_error(
+                        e, flag=self.handle_validation_error
+                    )
+            # Tool error (error raised at tool runtime)
+            else:
+                if isinstance(self.handle_tool_error, tuple):
+                    handled_types: tuple = self.handle_tool_error
+                elif callable(self.handle_tool_error):
+                    handled_types = _infer_handled_types(self.handle_tool_error)
+                else:
+                    handled_types = (ToolException,)
+                # Unhandled
+                if not self.handle_tool_error or not isinstance(e, handled_types):
+                    error_to_raise = e
+                # Handled
+                else:
+                    content = _handle_tool_error(e, flag=self.handle_tool_error)
 
         if error_to_raise:
             await run_manager.on_tool_error(error_to_raise)
@@ -842,11 +864,17 @@ def _handle_validation_error(
 
 
 def _handle_tool_error(
-    e: ToolException,
+    e: Exception,
     *,
-    flag: Optional[Union[Literal[True], str, Callable[[ToolException], str]]],
+    flag: Union[
+        None,
+        bool,
+        str,
+        Callable[..., str],
+        tuple[type[Exception], ...],
+    ],
 ) -> str:
-    if isinstance(flag, bool):
+    if isinstance(flag, (bool, tuple)):
         content = e.args[0] if e.args else "Tool execution error"
     elif isinstance(flag, str):
         content = flag
@@ -854,7 +882,7 @@ def _handle_tool_error(
         content = flag(e)
     else:
         msg = (
-            f"Got unexpected type of `handle_tool_error`. Expected bool, str "
+            f"Got unexpected type of `handle_tool_error`. Expected bool, str, tuple, "
             f"or callable. Received: {flag}"
         )
         raise ValueError(msg)
@@ -1050,3 +1078,24 @@ class BaseToolkit(BaseModel, ABC):
     @abstractmethod
     def get_tools(self) -> list[BaseTool]:
         """Get the tools in the toolkit."""
+
+
+def _infer_handled_types(handler: Callable[..., str]) -> tuple[type[Exception]]:
+    sig = inspect.signature(handler)
+    params = list(sig.parameters.values())
+    if params:
+        # If it's a method, the first argument is typically 'self' or 'cls'
+        if params[0].name in ["self", "cls"] and len(params) == 2:
+            first_param = params[1]
+        else:
+            first_param = params[0]
+
+        type_hints = get_type_hints(handler)
+        if first_param.name in type_hints:
+            if get_origin(first_param.annotation) is Union:
+                return tuple(get_args(first_param.annotation))
+            return (type_hints[first_param.name],)
+
+    # If no type information is available, return (ToolException,) for backwards
+    # compatibility.
+    return (ToolException,)

libs/core/langchain_core/tools/convert.py

@@ -18,6 +18,7 @@ def tool(
     response_format: Literal["content", "content_and_artifact"] = "content",
     parse_docstring: bool = False,
     error_on_invalid_docstring: bool = True,
+    **kwargs: Any,
 ) -> Callable:
     """Make tools out of functions, can be used with or without arguments.
 
@@ -42,6 +43,7 @@ def tool(
         error_on_invalid_docstring: if ``parse_docstring`` is provided, configure
             whether to raise ValueError on invalid Google Style docstrings.
             Defaults to True.
+        kwargs: Additional keyword arguments to pass to BaseTool constructor.
 
     Returns:
         The tool.
@@ -186,6 +188,7 @@ def tool(
                     response_format=response_format,
                     parse_docstring=parse_docstring,
                     error_on_invalid_docstring=error_on_invalid_docstring,
+                    **kwargs,
                 )
             # If someone doesn't want a schema applied, we must treat it as
             # a simple string->string function
@@ -202,6 +205,7 @@ def tool(
                 return_direct=return_direct,
                 coroutine=coroutine,
                 response_format=response_format,
+                **kwargs,
             )
 
         return _make_tool

libs/core/tests/unit_tests/test_tools.py

@@ -48,6 +48,7 @@ from langchain_core.tools.base import (
     InjectedToolArg,
     SchemaAnnotationError,
     _get_all_basemodel_annotations,
+    _infer_handled_types,
     _is_message_content_block,
     _is_message_content_type,
 )
@@ -766,6 +767,97 @@ async def test_async_exception_handling_callable() -> None:
     assert expected == actual
 
 
+def test_exception_handling_tuple() -> None:
+    @tool(handle_tool_error=(ValueError,))
+    def foo(x: int) -> int:
+        """X"""
+        msg = "bar"
+        raise ValueError(msg)
+
+    actual = foo.invoke({"x": 0})
+    expected = "bar"
+    assert actual == expected
+
+    @tool(handle_tool_error=True)
+    def foo2(x: int) -> int:
+        """X"""
+        msg = "bar"
+        raise ToolException(msg)
+
+    actual = foo2.invoke({"x": 0})
+    expected = "bar"
+    assert actual == expected
+
+    @tool(handle_tool_error=True)
+    def foo3(x: int) -> int:
+        """X"""
+        msg = "bar"
+        raise ValueError(msg)
+
+    with pytest.raises(ValueError):
+        foo3.invoke({"x": 0})
+
+
+def test_exception_handling_callable_type_hints() -> None:
+    def handle(e: ValueError) -> str:
+        return e.args[0]
+
+    @tool(handle_tool_error=handle)
+    def foo(x: int) -> int:
+        """X"""
+        msg = "bar"
+        raise ValueError(msg)
+
+    actual = foo.invoke({"x": 0})
+    expected = "bar"
+    assert actual == expected
+
+    def handle2(e: Union[ToolException, KeyError]) -> str:
+        return e.args[0]
+
+    @tool(handle_tool_error=handle2)
+    def foo2(x: int) -> int:
+        """X"""
+        msg = "bar"
+        raise ValueError(msg)
+
+    with pytest.raises(ValueError):
+        foo2.invoke({"x": 0})
+
+
+def test__infer_handled_types() -> None:
+    def handle(e):  # type: ignore
+        return ""
+
+    def handle2(e: Exception) -> str:
+        return ""
+
+    def handle3(e: Union[ValueError, ToolException]) -> str:
+        return ""
+
+    class Handler:
+        def handle(self, e: ValueError) -> str:
+            return ""
+
+    handle4 = Handler().handle
+
+    expected: tuple = (ToolException,)
+    actual = _infer_handled_types(handle)
+    assert expected == actual
+
+    expected = (Exception,)
+    actual = _infer_handled_types(handle2)
+    assert expected == actual
+
+    expected = (ValueError, ToolException)
+    actual = _infer_handled_types(handle3)
+    assert expected == actual
+
+    expected = (ValueError,)
+    actual = _infer_handled_types(handle4)
+    assert expected == actual
+
+
 async def test_async_exception_handling_non_tool_exception() -> None:
     _tool = _FakeExceptionTool(exception=ValueError())
     with pytest.raises(ValueError):