refactor: Tool Output Management: Add Component-Specific Variable for Conditional Tool Output (#4259)

Implement conditional tool output handling

- Updated `component.py` to check for `FEATURE_FLAGS.add_toolkit_output` and call `_append_tool_output` if the component has the `add_tool_output` attribute set to True.
- Ensured that the tool output behavior is correctly managed based on feature flags and component attributes in `custom_component.py`.

src/backend/base/langflow/custom/custom_component/component.py

@@ -91,9 +91,9 @@ class Component(CustomComponent):
         self.__inputs = inputs
         self.__config = config
         self._reset_all_output_values()
-        if FEATURE_FLAGS.add_toolkit_output and hasattr(self, "_append_tool_output"):
-            self._append_tool_output()
         super().__init__(**config)
+        if (FEATURE_FLAGS.add_toolkit_output) and hasattr(self, "_append_tool_output") and self.add_tool_output:
+            self._append_tool_output()
         if hasattr(self, "_trace_type"):
             self.trace_type = self._trace_type
         if not hasattr(self, "trace_type"):

src/backend/base/langflow/custom/custom_component/custom_component.py

@@ -59,6 +59,8 @@ class CustomComponent(BaseComponent):
     is_input: bool | None = None
     """The input state of the component. Defaults to None.
     If True, the component must have a field named 'input_value'."""
+    add_tool_output: bool | None = False
+    """Indicates whether the component will be treated as a tool. Defaults to False."""
     is_output: bool | None = None
     """The output state of the component. Defaults to None.
     If True, the component must have a field named 'input_value'."""

src/backend/tests/unit/test_custom_component_with_client.py

@@ -14,6 +14,16 @@ def code_component_with_multiple_outputs():
     return Component(_code=code)
 
 
+@pytest.fixture
+def code_component_with_multiple_outputs_with_add_tool_output():
+    code = Path("src/backend/tests/data/component_multiple_outputs.py").read_text(encoding="utf-8")
+    code = code.replace(
+        "class MultipleOutputsComponent(Component):",
+        "class MultipleOutputsComponent(Component):\n    add_tool_output = True",
+    )
+    return Component(_code=code)
+
+
 @pytest.fixture
 def component(
     client,  # noqa: ARG001
@@ -43,9 +53,14 @@ def test_list_flows_return_type(component):
     assert isinstance(flows, list)
 
 
-def test_feature_flags_add_toolkit_output(active_user, code_component_with_multiple_outputs):
+def test_feature_flags_add_toolkit_output(
+    active_user, code_component_with_multiple_outputs, code_component_with_multiple_outputs_with_add_tool_output
+):
     frontnd_node_dict, _ = build_custom_component_template(code_component_with_multiple_outputs, active_user.id)
     len_outputs = len(frontnd_node_dict["outputs"])
     FEATURE_FLAGS.add_toolkit_output = True
-    frontnd_node_dict, _ = build_custom_component_template(code_component_with_multiple_outputs, active_user.id)
+    code_component_with_multiple_outputs_with_add_tool_output.add_tool_output = True
+    frontnd_node_dict, _ = build_custom_component_template(
+        code_component_with_multiple_outputs_with_add_tool_output, active_user.id
+    )
     assert len(frontnd_node_dict["outputs"]) == len_outputs + 1