Add error function example in tools

docs/tools.md

@@ -320,3 +320,18 @@ When you create a function tool via `@function_tool`, you can pass a `failure_er
 -   If you explicitly pass `None`, then any tool call errors will be re-raised for you to handle. This could be a `ModelBehaviorError` if the model produced invalid JSON, or a `UserError` if your code crashed, etc.
 
 If you are manually creating a `FunctionTool` object, then you must handle errors inside the `on_invoke_tool` function.
+
+```python
+def sync_error_handler(ctx: RunContextWrapper[Any], error: Exception) -> str:
+    """Custom error handler that provides a formatted error message."""
+    return f"An error occurred: {error.__class__.__name__} - {str(error)}"
+
+@function_tool(failure_error_function=sync_error_handler)
+def get_latest_news():
+    """Get the latest news from the web."""
+    # This function might fail due to network issues, API limits, etc.
+    raise ConnectionError("Failed to connect to news service")
+
+# The error handler will be called if the tool fails
+# and will return: "An error occurred: ConnectionError - Failed to connect to news service"
+```

src/agents/handoffs.py

@@ -119,9 +119,9 @@ class Handoff(Generic[TContext, TAgent]):
     True, as it increases the likelihood of correct JSON input.
     """
 
-    is_enabled: bool | Callable[
-        [RunContextWrapper[Any], AgentBase[Any]], MaybeAwaitable[bool]
-    ] = True
+    is_enabled: bool | Callable[[RunContextWrapper[Any], AgentBase[Any]], MaybeAwaitable[bool]] = (
+        True
+    )
     """Whether the handoff is enabled. Either a bool or a Callable that takes the run context and
     agent and returns whether the handoff is enabled. You can use this to dynamically enable/disable
     a handoff based on your context/state."""

src/agents/run.py

@@ -1034,7 +1034,6 @@ async def _get_single_step_result_from_streamed_response(
         run_config: RunConfig,
         tool_use_tracker: AgentToolUseTracker,
     ) -> SingleStepResult:
-
         original_input = streamed_result.input
         pre_step_items = streamed_result.new_items
         event_queue = streamed_result._event_queue

src/agents/tracing/processors.py

@@ -70,8 +70,8 @@ def set_api_key(self, api_key: str):
                 client.
         """
         # Clear the cached property if it exists
-        if 'api_key' in self.__dict__:
-            del self.__dict__['api_key']
+        if "api_key" in self.__dict__:
+            del self.__dict__["api_key"]
 
         # Update the private attribute
         self._api_key = api_key

tests/test_agent_clone_shallow_copy.py

@@ -5,6 +5,7 @@
 def greet(name: str) -> str:
     return f"Hello, {name}!"
 
+
 def test_agent_clone_shallow_copy():
     """Test that clone creates shallow copy with tools.copy() workaround"""
     target_agent = Agent(name="Target")
@@ -16,9 +17,7 @@ def test_agent_clone_shallow_copy():
     )
 
     cloned = original.clone(
-        name="Cloned",
-        tools=original.tools.copy(),
-        handoffs=original.handoffs.copy()
+        name="Cloned", tools=original.tools.copy(), handoffs=original.handoffs.copy()
     )
 
     # Basic assertions

tests/test_stream_events.py

@@ -14,6 +14,7 @@ async def foo() -> str:
     await asyncio.sleep(3)
     return "success!"
 
+
 @pytest.mark.asyncio
 async def test_stream_events_main():
     model = FakeModel()