feat(simulation): add optional tools parameter to ToolSimulator (#208)

src/strands_evals/simulation/tool_simulator.py

@@ -166,6 +166,7 @@ def __init__(
         state_registry: StateRegistry | None = None,
         model: Model | str | None = None,
         max_tool_call_cache_size: int = 20,
+        tools: list | None = None,
     ):
         """
         Initialize a ToolSimulator instance.
@@ -178,8 +179,12 @@ def __init__(
                                      Only used when creating a new StateRegistry (ignored if state_registry
                                      is provided). Older calls are automatically evicted when limit is exceeded.
                                      Default is 20.
+            tools: Optional list of tools to provide to the internal simulation agent.
+                   When provided, the agent can use these tools (e.g. calculator) to improve
+                   accuracy of generated responses. Defaults to an empty list.
         """
         self.model = model
+        self.tools = tools or []
         self.state_registry = state_registry or StateRegistry(max_tool_call_cache_size=max_tool_call_cache_size)
         self._registered_tools: dict[str, RegisteredTool] = {}
 
@@ -229,7 +234,7 @@ def wrapper(*args, **kwargs):
     def _simulate_tool_call(self, prompt: str, structured_output_model=None) -> Any:
         """Tool simulation agent creation and response generation."""
         agent = Agent(
-            tools=[],
+            tools=self.tools,
             model=self.model,
             callback_handler=None,
         )

tests/strands_evals/simulation/test_tool_simulator.py

@@ -465,3 +465,75 @@ def test_tool_no_params() -> dict:
     properties = schema.get("properties", {})
     # Empty model should mean no properties
     assert len(properties) == 0, "Tool with empty schema should have no properties"
+
+
+def test_tool_simulator_init_default_tools():
+    """Test ToolSimulator initializes with empty tools list by default."""
+    simulator = ToolSimulator()
+    assert simulator.tools == []
+
+
+def test_tool_simulator_init_with_tools():
+    """Test ToolSimulator stores provided tools."""
+    mock_tool = MagicMock()
+    simulator = ToolSimulator(tools=[mock_tool])
+    assert simulator.tools == [mock_tool]
+
+
+def test_tool_simulator_init_tools_none_becomes_empty_list():
+    """Test ToolSimulator converts None tools to empty list."""
+    simulator = ToolSimulator(tools=None)
+    assert simulator.tools == []
+
+
+def test_simulate_tool_call_passes_tools_to_agent(mock_model):
+    """Test that tools are passed through to the internal Agent."""
+    mock_tool = MagicMock()
+    simulator = ToolSimulator(model=mock_model, tools=[mock_tool])
+
+    @simulator.tool(output_schema=GenericOutput)
+    def test_func(message: str) -> dict:
+        """Test function."""
+        pass
+
+    captured_kwargs = {}
+
+    def mock_agent_constructor(**kwargs):
+        captured_kwargs.update(kwargs)
+        mock_agent = MagicMock()
+        mock_result = MagicMock()
+        mock_result.__str__ = MagicMock(return_value='{"result": "response"}')
+        mock_agent.return_value = mock_result
+        return mock_agent
+
+    with pytest.MonkeyPatch().context() as m:
+        m.setattr("strands_evals.simulation.tool_simulator.Agent", mock_agent_constructor)
+        simulator.test_func("hello")
+
+    assert captured_kwargs["tools"] == [mock_tool]
+
+
+def test_simulate_tool_call_default_empty_tools(mock_model):
+    """Test that default simulator passes empty tools list to Agent."""
+    simulator = ToolSimulator(model=mock_model)
+
+    @simulator.tool(output_schema=GenericOutput)
+    def test_func(message: str) -> dict:
+        """Test function."""
+        pass
+
+    captured_kwargs = {}
+
+    def mock_agent_constructor(**kwargs):
+        captured_kwargs.update(kwargs)
+        mock_agent = MagicMock()
+        mock_result = MagicMock()
+        mock_result.__str__ = MagicMock(return_value='{"result": "response"}')
+        mock_agent.return_value = mock_result
+        return mock_agent
+
+    with pytest.MonkeyPatch().context() as m:
+        m.setattr("strands_evals.simulation.tool_simulator.Agent", mock_agent_constructor)
+        simulator.test_func("hello")
+
+    assert captured_kwargs["tools"] == []