Fix #3883: Add compatibility alias for tool decorator in crewai_tools

- Add tool function to crewai_tools/__init__.py that forwards to crewai.tools.tool
- Implement lazy import to avoid import-time side effects
- Add deprecation warning directing users to canonical import path
- Add comprehensive test coverage for the tool alias
- All tests passing (212 passed, 1 skipped)

The tool decorator can now be imported from crewai_tools for backward compatibility,
while users are encouraged to use 'from crewai.tools import tool' going forward.

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

lib/crewai-tools/src/crewai_tools/__init__.py

@@ -285,6 +285,52 @@ __all__ = [
     "YoutubeVideoSearchTool",
     "ZapierActionTool",
     "ZapierActionTools",
+    "tool",
 ]
 
 __version__ = "1.4.1"
+
+
+def tool(*args, result_as_answer: bool = False, max_usage_count: int | None = None):
+    """
+    Compatibility alias for the tool decorator from crewai.tools.
+
+    This function provides backward compatibility for users who import tool from crewai_tools.
+    The canonical import path is 'from crewai.tools import tool'.
+
+    Args:
+        *args: Positional arguments for the tool decorator.
+        result_as_answer: Flag to indicate if the tool result should be used as the final agent answer.
+        max_usage_count: Maximum number of times this tool can be used. None means unlimited usage.
+
+    Returns:
+        The tool decorator from crewai.tools.
+
+    Example:
+        >>> from crewai_tools import tool
+        >>> @tool
+        ... def my_tool(question: str) -> str:
+        ...     '''Answer a question'''
+        ...     return f"Answer to: {question}"
+
+    Note:
+        This is a compatibility alias. Please use 'from crewai.tools import tool' instead.
+    """
+    import warnings
+
+    warnings.warn(
+        "Importing 'tool' from 'crewai_tools' is deprecated. "
+        "Please use 'from crewai.tools import tool' instead.",
+        DeprecationWarning,
+        stacklevel=2,
+    )
+
+    from crewai.tools import tool as core_tool
+
+    kwargs = {}
+    if result_as_answer:
+        kwargs["result_as_answer"] = result_as_answer
+    if max_usage_count is not None:
+        kwargs["max_usage_count"] = max_usage_count
+
+    return core_tool(*args, **kwargs)

lib/crewai-tools/tests/test_tool_alias.py

@@ -0,0 +1,153 @@
+"""Tests for the tool decorator compatibility alias in crewai_tools."""
+
+import warnings
+
+import pytest
+from crewai.tools import BaseTool
+
+
+def test_tool_import_from_crewai_tools():
+    """Test that tool can be imported from crewai_tools."""
+    from crewai_tools import tool
+
+    assert callable(tool)
+
+
+def test_tool_decorator_basic_usage():
+    """Test that the tool decorator works with basic usage."""
+    from crewai_tools import tool
+
+    with warnings.catch_warnings(record=True) as w:
+        warnings.simplefilter("always")
+
+        @tool
+        def my_tool(question: str) -> str:
+            """Answer a question."""
+            return f"Answer to: {question}"
+
+        assert len(w) == 1
+        assert issubclass(w[0].category, DeprecationWarning)
+        assert "from crewai.tools import tool" in str(w[0].message)
+
+    assert isinstance(my_tool, BaseTool)
+    assert my_tool.name == "my_tool"
+    assert "Answer a question" in my_tool.description
+    assert my_tool.func("test") == "Answer to: test"
+
+
+def test_tool_decorator_with_name():
+    """Test that the tool decorator works with a custom name."""
+    from crewai_tools import tool
+
+    with warnings.catch_warnings(record=True) as w:
+        warnings.simplefilter("always")
+
+        @tool("Custom Tool Name")
+        def my_tool(question: str) -> str:
+            """Answer a question."""
+            return f"Answer to: {question}"
+
+        assert len(w) == 1
+        assert issubclass(w[0].category, DeprecationWarning)
+
+    assert isinstance(my_tool, BaseTool)
+    assert my_tool.name == "Custom Tool Name"
+    assert "Answer a question" in my_tool.description
+    assert my_tool.func("test") == "Answer to: test"
+
+
+def test_tool_decorator_with_result_as_answer():
+    """Test that the tool decorator works with result_as_answer parameter."""
+    from crewai_tools import tool
+
+    with warnings.catch_warnings(record=True) as w:
+        warnings.simplefilter("always")
+
+        @tool("My Tool", result_as_answer=True)
+        def my_tool(question: str) -> str:
+            """Answer a question."""
+            return f"Answer to: {question}"
+
+        assert len(w) == 1
+
+    assert isinstance(my_tool, BaseTool)
+    assert my_tool.name == "My Tool"
+    assert my_tool.result_as_answer is True
+
+
+def test_tool_decorator_with_max_usage_count():
+    """Test that the tool decorator works with max_usage_count parameter."""
+    from crewai_tools import tool
+
+    with warnings.catch_warnings(record=True) as w:
+        warnings.simplefilter("always")
+
+        @tool("My Tool", max_usage_count=5)
+        def my_tool(question: str) -> str:
+            """Answer a question."""
+            return f"Answer to: {question}"
+
+        assert len(w) == 1
+
+    assert isinstance(my_tool, BaseTool)
+    assert my_tool.name == "My Tool"
+    assert my_tool.max_usage_count == 5
+    assert my_tool.current_usage_count == 0
+
+
+def test_tool_decorator_with_all_parameters():
+    """Test that the tool decorator works with all parameters."""
+    from crewai_tools import tool
+
+    with warnings.catch_warnings(record=True) as w:
+        warnings.simplefilter("always")
+
+        @tool("Custom Name", result_as_answer=True, max_usage_count=3)
+        def my_tool(question: str) -> str:
+            """Answer a question."""
+            return f"Answer to: {question}"
+
+        assert len(w) == 1
+
+    assert isinstance(my_tool, BaseTool)
+    assert my_tool.name == "Custom Name"
+    assert my_tool.result_as_answer is True
+    assert my_tool.max_usage_count == 3
+
+
+def test_tool_alias_matches_core_behavior():
+    """Test that the alias behaves identically to the core tool decorator."""
+    from crewai.tools import tool as core_tool
+    from crewai_tools import tool as alias_tool
+
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
+
+        @alias_tool
+        def my_test_tool(question: str) -> str:
+            """Answer a question."""
+            return f"Answer: {question}"
+
+    @core_tool
+    def my_test_tool_core(question: str) -> str:
+        """Answer a question."""
+        return f"Answer: {question}"
+
+    assert type(my_test_tool) == type(my_test_tool_core)
+    assert my_test_tool.func("test") == my_test_tool_core.func("test")
+    assert my_test_tool.result_as_answer == my_test_tool_core.result_as_answer
+    assert my_test_tool.max_usage_count == my_test_tool_core.max_usage_count
+
+
+def test_tool_requires_docstring():
+    """Test that the tool decorator requires a docstring."""
+    from crewai_tools import tool
+
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
+
+        with pytest.raises(ValueError, match="Function must have a docstring"):
+
+            @tool
+            def my_tool(question: str) -> str:
+                return f"Answer to: {question}"