Model-Adaptive Tool Necessity Reveals the Knowing-Doing Gap in LLM Tool Use

ArXi:2605.14038v1 Announce Type: new Large language models (LLMs) increasingly act as autonomous agents that must decide when to answer directly vs. when to invoke external tools. Prior work studying adaptive tool use has largely treated tool necessity as a model-agnostic property, annotated by human or LLM judge, and mostly cover cases where the answer is obvious (e.g., fetching the weather vs. paraphrasing text