Depends heavily on the complexity of your tool interface. The real power of agentic systems is not so much in their ability to select and call tools, but the expressiveness with which they can (generatively) parameterize them meaningfully in novel ways. For simple "do this or that" stuff sure, but then that could just be distilled to a deterministic workflow. There could be a world where SLMs fit into a larger system, but anything requiring sufficient creativity and exploration will still require frontier models for frontier results.