What is a Tool Use (AI)?

Where tool calling describes the mechanical act of invoking a specific function, tool use describes the model's higher-level judgment: recognizing that a question needs a live lookup rather than a memorized answer, choosing among several available tools, sequencing multiple tool calls to complete a multi-step task, and knowing when it has enough information to stop and respond. This judgment is what most differentiates a capable agent from a simple chatbot wrapped around a set of functions. Good tool use also includes recovering from a failed or empty tool result, whether by retrying with different arguments, falling back to a different tool, or telling the user what went wrong, rather than either hallucinating an answer or looping indefinitely. As agents are given more tools, the harder problem shifts from execution to selection, since picking the right tool from a large library gets harder as similarly named tools multiply.