catch exceptions properly

libs/core/langchain_core/tools/base.py

@@ -543,43 +543,54 @@ class ChildTool(BaseTool):
         artifact = None
         error_to_raise: Union[Exception, KeyboardInterrupt, None] = None
         try:
-            child_config = patch_config(config, callbacks=run_manager.get_child())
-            context = copy_context()
-            context.run(_set_config_context, child_config)
-            tool_args, tool_kwargs = self._to_args_and_kwargs(tool_input)
-            if signature(self._run).parameters.get("run_manager"):
-                tool_kwargs["run_manager"] = run_manager
+            try:
+                child_config = patch_config(config, callbacks=run_manager.get_child())
+                context = copy_context()
+                context.run(_set_config_context, child_config)
+                tool_args, tool_kwargs = self._to_args_and_kwargs(tool_input)
+                if signature(self._run).parameters.get("run_manager"):
+                    tool_kwargs["run_manager"] = run_manager
 
-            if config_param := _get_runnable_config_param(self._run):
-                tool_kwargs[config_param] = config
-            response = context.run(self._run, *tool_args, **tool_kwargs)
-            if self.response_format == "content_and_artifact":
-                if not isinstance(response, tuple) or len(response) != 2:
-                    raise ValueError(
-                        "Since response_format='content_and_artifact' "
-                        "a two-tuple of the message content and raw tool output is "
-                        f"expected. Instead generated response of type: "
-                        f"{type(response)}."
+                if config_param := _get_runnable_config_param(self._run):
+                    tool_kwargs[config_param] = config
+                response = context.run(self._run, *tool_args, **tool_kwargs)
+                if self.response_format == "content_and_artifact":
+                    if not isinstance(response, tuple) or len(response) != 2:
+                        raise ValueError(
+                            "Since response_format='content_and_artifact' "
+                            "a two-tuple of the message content and raw tool output is "
+                            f"expected. Instead generated response of type: "
+                            f"{type(response)}."
+                        )
+                    content, artifact = response
+                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
                     )
-                content, artifact = response
-            else:
-                content = response
-            status = "success"
-        except ValidationError as e:
-            if not 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 as e:
+                raise ToolException(str(e)) from e
+            except KeyboardInterrupt as e:
                 error_to_raise = e
-            else:
-                content = _handle_validation_error(e, flag=self.handle_validation_error)
-            status = "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"
 
         if error_to_raise:
             run_manager.on_tool_error(error_to_raise)
@@ -652,50 +663,61 @@ class ChildTool(BaseTool):
         artifact = None
         error_to_raise: Optional[Union[Exception, KeyboardInterrupt]] = None
         try:
-            tool_args, tool_kwargs = self._to_args_and_kwargs(tool_input)
-            child_config = patch_config(config, callbacks=run_manager.get_child())
-            context = copy_context()
-            context.run(_set_config_context, child_config)
-            func_to_check = (
-                self._run if self.__class__._arun is BaseTool._arun else self._arun
-            )
-            if signature(func_to_check).parameters.get("run_manager"):
-                tool_kwargs["run_manager"] = run_manager
-            if config_param := _get_runnable_config_param(func_to_check):
-                tool_kwargs[config_param] = config
+            try:
+                tool_args, tool_kwargs = self._to_args_and_kwargs(tool_input)
+                child_config = patch_config(config, callbacks=run_manager.get_child())
+                context = copy_context()
+                context.run(_set_config_context, child_config)
+                func_to_check = (
+                    self._run if self.__class__._arun is BaseTool._arun else self._arun
+                )
+                if signature(func_to_check).parameters.get("run_manager"):
+                    tool_kwargs["run_manager"] = run_manager
+                if config_param := _get_runnable_config_param(func_to_check):
+                    tool_kwargs[config_param] = config
 
-            coro = context.run(self._arun, *tool_args, **tool_kwargs)
-            if asyncio_accepts_context():
-                response = await asyncio.create_task(coro, context=context)  # type: ignore
-            else:
-                response = await coro
-            if self.response_format == "content_and_artifact":
-                if not isinstance(response, tuple) or len(response) != 2:
-                    raise ValueError(
-                        "Since response_format='content_and_artifact' "
-                        "a two-tuple of the message content and raw tool output is "
-                        f"expected. Instead generated response of type: "
-                        f"{type(response)}."
+                coro = context.run(self._arun, *tool_args, **tool_kwargs)
+                if asyncio_accepts_context():
+                    response = await asyncio.create_task(coro, context=context)  # type: ignore
+                else:
+                    response = await coro
+                if self.response_format == "content_and_artifact":
+                    if not isinstance(response, tuple) or len(response) != 2:
+                        raise ValueError(
+                            "Since response_format='content_and_artifact' "
+                            "a two-tuple of the message content and raw tool output is "
+                            f"expected. Instead generated response of type: "
+                            f"{type(response)}."
+                        )
+                    content, artifact = response
+                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
                     )
-                content, artifact = response
-            else:
-                content = response
-            status = "success"
-        except ValidationError as e:
-            if not 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 as e:
+                raise ToolException(str(e)) from e
+            except KeyboardInterrupt as e:
                 error_to_raise = e
-            else:
-                content = _handle_validation_error(e, flag=self.handle_validation_error)
-            status = "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"
 
         if error_to_raise:
             await run_manager.on_tool_error(error_to_raise)

libs/core/langchain_core/tools/convert.py

@@ -2,9 +2,9 @@ import inspect
 from typing import Any, Callable, Dict, Literal, Optional, Type, Union, get_type_hints
 
 from langchain_core.callbacks import Callbacks
-from langchain_core.pydantic_v1 import BaseModel, Field, create_model
+from langchain_core.pydantic_v1 import BaseModel, Field, ValidationError, create_model
 from langchain_core.runnables import Runnable
-from langchain_core.tools.base import BaseTool
+from langchain_core.tools.base import BaseTool, ToolException
 from langchain_core.tools.simple import Tool
 from langchain_core.tools.structured import StructuredTool
 
@@ -17,6 +17,12 @@ def tool(
     response_format: Literal["content", "content_and_artifact"] = "content",
     parse_docstring: bool = False,
     error_on_invalid_docstring: bool = True,
+    handle_tool_error: Optional[
+        Union[bool, str, Callable[[ToolException], str]]
+    ] = False,
+    handle_validation_error: Optional[
+        Union[bool, str, Callable[[ValidationError], str]]
+    ] = False,
 ) -> Callable:
     """Make tools out of functions, can be used with or without arguments.
 
@@ -41,6 +47,15 @@ def tool(
         error_on_invalid_docstring: if ``parse_docstring`` is provided, configure
             whether to raise ValueError on invalid Google Style docstrings.
             Defaults to True.
+        handle_tool_error: Handle the content of the ToolException thrown. If False
+            do nothing, If True returns 'Tool execution error'. If string then
+            returns that string directly, if callable converts error to string to be returned.
+            Defaults to False.
+        handle_validation_error: Handle the content of the ValidationError thrown. If False
+            do nothing, If True returns 'Tool input validation error'. If string then
+            returns that string directly, if callable converts error to string to be returned.
+            Defaults to False.
+
 
     Returns:
         The tool.
@@ -137,7 +152,7 @@ def tool(
                     monkey: The baz.
                 \"\"\"
                 return bar
-    """
+    """  # noqa: E501
 
     def _make_with_name(tool_name: str) -> Callable:
         def _make_tool(dec_func: Union[Callable, Runnable]) -> BaseTool:
@@ -184,6 +199,8 @@ def tool(
                     response_format=response_format,
                     parse_docstring=parse_docstring,
                     error_on_invalid_docstring=error_on_invalid_docstring,
+                    handle_tool_error=handle_tool_error,
+                    handle_validation_error=handle_validation_error,
                 )
             # If someone doesn't want a schema applied, we must treat it as
             # a simple string->string function

libs/core/tests/unit_tests/test_tools.py

@@ -679,7 +679,7 @@ def test_exception_handling_callable() -> None:
 
 def test_exception_handling_non_tool_exception() -> None:
     _tool = _FakeExceptionTool(exception=ValueError())
-    with pytest.raises(ValueError):
+    with pytest.raises(ToolException):
         _tool.run({})
 
 
@@ -710,7 +710,7 @@ async def test_async_exception_handling_callable() -> None:
 
 async def test_async_exception_handling_non_tool_exception() -> None:
     _tool = _FakeExceptionTool(exception=ValueError())
-    with pytest.raises(ValueError):
+    with pytest.raises(ToolException):
         await _tool.arun({})
 
 
@@ -806,7 +806,7 @@ def test_validation_error_handling_non_validation_error(
             return "dummy"
 
     _tool = _RaiseNonValidationErrorTool(handle_validation_error=handler)  # type: ignore[call-arg]
-    with pytest.raises(NotImplementedError):
+    with pytest.raises(ToolException):
         _tool.run({})
 
 
@@ -868,7 +868,7 @@ async def test_async_validation_error_handling_non_validation_error(
             return "dummy"
 
     _tool = _RaiseNonValidationErrorTool(handle_validation_error=handler)  # type: ignore[call-arg]
-    with pytest.raises(NotImplementedError):
+    with pytest.raises(ToolException):
         await _tool.arun({})
 
 
@@ -1408,10 +1408,8 @@ def test_tool_injected_arg_without_schema(tool_: BaseTool) -> None:
     assert tool_.invoke(
         {"name": "foo", "args": {"x": 5, "y": "bar"}, "id": "123", "type": "tool_call"}
     ) == ToolMessage("bar", tool_call_id="123", name="foo")
-    expected_error = (
-        ValidationError if not isinstance(tool_, InjectedTool) else TypeError
-    )
-    with pytest.raises(expected_error):
+
+    with pytest.raises(ToolException):
         tool_.invoke({"x": 5})
 
     assert convert_to_openai_function(tool_) == {
@@ -1873,7 +1871,6 @@ def test__get_all_basemodel_annotations_v1() -> None:
 def test_tool_args_schema_pydantic_v2_with_metadata() -> None:
     from pydantic import BaseModel as BaseModelV2  # pydantic: ignore
     from pydantic import Field as FieldV2  # pydantic: ignore
-    from pydantic import ValidationError as ValidationErrorV2  # pydantic: ignore
 
     class Foo(BaseModelV2):
         x: List[int] = FieldV2(
@@ -1903,7 +1900,7 @@ def test_tool_args_schema_pydantic_v2_with_metadata() -> None:
     }
 
     assert foo.invoke({"x": [0] * 10})
-    with pytest.raises(ValidationErrorV2):
+    with pytest.raises(ToolException):
         foo.invoke({"x": [0] * 9})