The ToolMonitorRubric is created in ToolEnv.__init__ before subclasses add their tools. When SandboxEnv or PythonEnv call super().__init__(), self.tools is empty, so ToolMonitorRubric captures an empty tool_names list. Tools like bash and python are added via add_tool() only after the rubric is created, so their per-tool call counts won't be tracked. This is a regression from the old pattern where ToolRubric was explicitly created after the environment was fully initialized in math_python.py.