The LLM+tools approach may face limitations such as confusion in reasoning due to a large number of tools and in-context examples, difficulty in debugging complex reasoning errors, and challenges in adapting to new tasks without extensive retraining. HAMMR's design addresses these limitations by introducing a hierarchical and compositional approach. By breaking down the reasoning process into specialized agents and enabling them to call upon each other, HAMMR simplifies the reasoning chain, making it easier to develop and debug individual agents. This modular design also allows for better reuse of tools and reasoning patterns, enhancing the system's adaptability to new tasks without the need for extensive retraining.