Fix duplicate tool execution in structured_tool.invoke()

- Remove duplicate function call on line 285 that caused tools to execute twice
- Add comprehensive test to prevent regression
- Fixes issue #3489

Co-Authored-By: João <joao@crewai.com>

src/crewai/tools/structured_tool.py

@@ -282,8 +282,6 @@ class CrewStructuredTool:
         except Exception:
             raise
 
-        result = self.func(**parsed_args, **kwargs)
-
         if asyncio.iscoroutine(result):
             return asyncio.run(result)
 

tests/tools/test_structured_tool.py

@@ -144,6 +144,32 @@ def test_default_values_in_schema():
     )
     assert result == "test custom 42"
 
+
+def test_tool_not_executed_twice():
+    """Test that tool function is only executed once per invoke call (bug #3489)"""
+    call_count = 0
+    
+    def counting_func(param: str) -> str:
+        """Function that counts how many times it's called."""
+        nonlocal call_count
+        call_count += 1
+        return f"Called {call_count} times with {param}"
+    
+    tool = CrewStructuredTool.from_function(
+        func=counting_func, name="counting_tool", description="Counts calls"
+    )
+    
+    call_count = 0
+    
+    result = tool.invoke({"param": "test"})
+    
+    assert call_count == 1, f"Expected function to be called once, but was called {call_count} times"
+    assert result == "Called 1 times with test"
+    
+    result = tool.invoke({"param": "test2"})
+    assert call_count == 2, f"Expected function to be called twice total, but was called {call_count} times"
+    assert result == "Called 2 times with test2"
+
 @pytest.fixture
 def custom_tool_decorator():
     from crewai.tools import tool
@@ -227,4 +253,4 @@ def test_async_tool_using_decorator_within_flow(custom_tool_decorator):
 
     flow = StructuredExampleFlow()
     result = flow.kickoff()
-    assert result.raw == "Hello World from Custom Tool"
+    assert result.raw == "Hello World from Custom Tool"